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  • Did we always have to register to download the Java 5 JDK, or is this new Oracle fun?

    - by Ukko
    I could swear that just a couple of months ago I downloaded a copy of the Java 1.5 SE JDK and I did not have to give them information on my first born. Today, I had to go through the register-and-we-will-send-you-a-link-someday dance. I have not received the link yet, so I thought I would ask about it here. What is special about the Java 5 JDK? I can get 6 just by clicking, is this a stick to get us to migrate to Java 6? Am I just not remembering doing this before? What marketing genius thought this would be a value add for Java? "If we make them sweat for the JDK they won't just delete it willy-nilly the next time?" Does everyone picture the people designing systems like this as mustache twirling Snidely Whiplash clones like I do? Did I just miss the link for the Secret Squirrel route to the download page? Finally, I am in the U.S. so I should not have to worry about export restrictions. Any thoughts?

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  • How to test if a string is inside a list of predinfined list of string in oracle pl/sql

    - by drupalspring
    I define a list a string which contains different country codes ( for example , USA ,CHINA ,HK ,JPN) How can I check that if a input variable equal to one of the country of the country list in pl/sql . I use the following code to test it but fail, how can I revise it? declare country_list CONSTANT VARCHAR2(200) := USA,CHINA,HK,JPN; input VARCHAR2(200); begin input := 'JPN'; IF input IN (country_list) DBMS_OUTPUT.PUT_LINE('It is Inside'); else DBMS_OUTPUT.PUT_LINE('It is not Inside'); END IF; end;

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  • How to convert rows returned by a query into columns in oracle?

    - by Piyush Lohana
    I have to display the results of the below query as columns. select to_char(sysdate + 1 - rownum,'MON-YYYY') as d from all_objects where trunc(sysdate + 1 - rownum,'MM') = trunc(to_date(:from_date,'MON-YYYY'),'MM') minus select to_char(sysdate + 1 - rownum,'MON-YYYY') as d from all_objects where trunc(sysdate + 1 - rownum,'MM') trunc(to_date(':to_date','MON-YYYY'),'MM') Please help me in figuring that out.

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  • ORACLE:- 'SELECT ORDER BY ASC' but 'USA' always first.

    - by Robert
    I have to write a drop down query for countries. But USA should always be first. The rest of the countries are in alphabetical order I tried the following query SELECT countries_id ,countries_name FROM get_countries WHERE countries_id = 138 UNION SELECT countries_id ,countries_name FROM get_countries WHERE countries_id != 138 ORDER BY 2 ASC

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  • PHP: How do I find (Oracle) parameters in a SQL query?

    - by Bartb
    Suppose you have a string: "SELECT * FROM TABLE WHERE column1 = :var1 AND column2 = :var2" Now, how do I get an array with all the variables like so: Array ( [0] => :var1 [1] => :var2 ) I've tried it with PHP's preg_match_all, but I struggle with the regex. $varcount = preg_match_all("/ :.+ /", $sql, $out);

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  • ORACLE:- 'SELECT ODER BY ASC' but 'USA' always first.

    - by Robert
    I have to write a drop down query for countries. But USA hould always be first. The rest of the countries are in alphabetical order I tried the following query SELECT countries_id ,countries_name FROM get_countries WHERE countries_id = 138 UNION SELECT countries_id ,countries_name FROM get_countries WHERE countries_id != 138 ORDER BY 2 ASC

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  • value types in the vm

    - by john.rose
    value types in the vm p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Times} p.p2 {margin: 0.0px 0.0px 14.0px 0.0px; font: 14.0px Times} p.p3 {margin: 0.0px 0.0px 12.0px 0.0px; font: 14.0px Times} p.p4 {margin: 0.0px 0.0px 15.0px 0.0px; font: 14.0px Times} p.p5 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Courier} p.p6 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Courier; min-height: 17.0px} p.p7 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Times; min-height: 18.0px} p.p8 {margin: 0.0px 0.0px 0.0px 36.0px; text-indent: -36.0px; font: 14.0px Times; min-height: 18.0px} p.p9 {margin: 0.0px 0.0px 12.0px 0.0px; font: 14.0px Times; min-height: 18.0px} p.p10 {margin: 0.0px 0.0px 12.0px 0.0px; font: 14.0px Times; color: #000000} li.li1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Times} li.li7 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Times; min-height: 18.0px} span.s1 {font: 14.0px Courier} span.s2 {color: #000000} span.s3 {font: 14.0px Courier; color: #000000} ol.ol1 {list-style-type: decimal} Or, enduring values for a changing world. Introduction A value type is a data type which, generally speaking, is designed for being passed by value in and out of methods, and stored by value in data structures. The only value types which the Java language directly supports are the eight primitive types. Java indirectly and approximately supports value types, if they are implemented in terms of classes. For example, both Integer and String may be viewed as value types, especially if their usage is restricted to avoid operations appropriate to Object. In this note, we propose a definition of value types in terms of a design pattern for Java classes, accompanied by a set of usage restrictions. We also sketch the relation of such value types to tuple types (which are a JVM-level notion), and point out JVM optimizations that can apply to value types. This note is a thought experiment to extend the JVM’s performance model in support of value types. The demonstration has two phases.  Initially the extension can simply use design patterns, within the current bytecode architecture, and in today’s Java language. But if the performance model is to be realized in practice, it will probably require new JVM bytecode features, changes to the Java language, or both.  We will look at a few possibilities for these new features. An Axiom of Value In the context of the JVM, a value type is a data type equipped with construction, assignment, and equality operations, and a set of typed components, such that, whenever two variables of the value type produce equal corresponding values for their components, the values of the two variables cannot be distinguished by any JVM operation. Here are some corollaries: A value type is immutable, since otherwise a copy could be constructed and the original could be modified in one of its components, allowing the copies to be distinguished. Changing the component of a value type requires construction of a new value. The equals and hashCode operations are strictly component-wise. If a value type is represented by a JVM reference, that reference cannot be successfully synchronized on, and cannot be usefully compared for reference equality. A value type can be viewed in terms of what it doesn’t do. We can say that a value type omits all value-unsafe operations, which could violate the constraints on value types.  These operations, which are ordinarily allowed for Java object types, are pointer equality comparison (the acmp instruction), synchronization (the monitor instructions), all the wait and notify methods of class Object, and non-trivial finalize methods. The clone method is also value-unsafe, although for value types it could be treated as the identity function. Finally, and most importantly, any side effect on an object (however visible) also counts as an value-unsafe operation. A value type may have methods, but such methods must not change the components of the value. It is reasonable and useful to define methods like toString, equals, and hashCode on value types, and also methods which are specifically valuable to users of the value type. Representations of Value Value types have two natural representations in the JVM, unboxed and boxed. An unboxed value consists of the components, as simple variables. For example, the complex number x=(1+2i), in rectangular coordinate form, may be represented in unboxed form by the following pair of variables: /*Complex x = Complex.valueOf(1.0, 2.0):*/ double x_re = 1.0, x_im = 2.0; These variables might be locals, parameters, or fields. Their association as components of a single value is not defined to the JVM. Here is a sample computation which computes the norm of the difference between two complex numbers: double distance(/*Complex x:*/ double x_re, double x_im,         /*Complex y:*/ double y_re, double y_im) {     /*Complex z = x.minus(y):*/     double z_re = x_re - y_re, z_im = x_im - y_im;     /*return z.abs():*/     return Math.sqrt(z_re*z_re + z_im*z_im); } A boxed representation groups component values under a single object reference. The reference is to a ‘wrapper class’ that carries the component values in its fields. (A primitive type can naturally be equated with a trivial value type with just one component of that type. In that view, the wrapper class Integer can serve as a boxed representation of value type int.) The unboxed representation of complex numbers is practical for many uses, but it fails to cover several major use cases: return values, array elements, and generic APIs. The two components of a complex number cannot be directly returned from a Java function, since Java does not support multiple return values. The same story applies to array elements: Java has no ’array of structs’ feature. (Double-length arrays are a possible workaround for complex numbers, but not for value types with heterogeneous components.) By generic APIs I mean both those which use generic types, like Arrays.asList and those which have special case support for primitive types, like String.valueOf and PrintStream.println. Those APIs do not support unboxed values, and offer some problems to boxed values. Any ’real’ JVM type should have a story for returns, arrays, and API interoperability. The basic problem here is that value types fall between primitive types and object types. Value types are clearly more complex than primitive types, and object types are slightly too complicated. Objects are a little bit dangerous to use as value carriers, since object references can be compared for pointer equality, and can be synchronized on. Also, as many Java programmers have observed, there is often a performance cost to using wrapper objects, even on modern JVMs. Even so, wrapper classes are a good starting point for talking about value types. If there were a set of structural rules and restrictions which would prevent value-unsafe operations on value types, wrapper classes would provide a good notation for defining value types. This note attempts to define such rules and restrictions. Let’s Start Coding Now it is time to look at some real code. Here is a definition, written in Java, of a complex number value type. @ValueSafe public final class Complex implements java.io.Serializable {     // immutable component structure:     public final double re, im;     private Complex(double re, double im) {         this.re = re; this.im = im;     }     // interoperability methods:     public String toString() { return "Complex("+re+","+im+")"; }     public List<Double> asList() { return Arrays.asList(re, im); }     public boolean equals(Complex c) {         return re == c.re && im == c.im;     }     public boolean equals(@ValueSafe Object x) {         return x instanceof Complex && equals((Complex) x);     }     public int hashCode() {         return 31*Double.valueOf(re).hashCode()                 + Double.valueOf(im).hashCode();     }     // factory methods:     public static Complex valueOf(double re, double im) {         return new Complex(re, im);     }     public Complex changeRe(double re2) { return valueOf(re2, im); }     public Complex changeIm(double im2) { return valueOf(re, im2); }     public static Complex cast(@ValueSafe Object x) {         return x == null ? ZERO : (Complex) x;     }     // utility methods and constants:     public Complex plus(Complex c)  { return new Complex(re+c.re, im+c.im); }     public Complex minus(Complex c) { return new Complex(re-c.re, im-c.im); }     public double abs() { return Math.sqrt(re*re + im*im); }     public static final Complex PI = valueOf(Math.PI, 0.0);     public static final Complex ZERO = valueOf(0.0, 0.0); } This is not a minimal definition, because it includes some utility methods and other optional parts.  The essential elements are as follows: The class is marked as a value type with an annotation. The class is final, because it does not make sense to create subclasses of value types. The fields of the class are all non-private and final.  (I.e., the type is immutable and structurally transparent.) From the supertype Object, all public non-final methods are overridden. The constructor is private. Beyond these bare essentials, we can observe the following features in this example, which are likely to be typical of all value types: One or more factory methods are responsible for value creation, including a component-wise valueOf method. There are utility methods for complex arithmetic and instance creation, such as plus and changeIm. There are static utility constants, such as PI. The type is serializable, using the default mechanisms. There are methods for converting to and from dynamically typed references, such as asList and cast. The Rules In order to use value types properly, the programmer must avoid value-unsafe operations.  A helpful Java compiler should issue errors (or at least warnings) for code which provably applies value-unsafe operations, and should issue warnings for code which might be correct but does not provably avoid value-unsafe operations.  No such compilers exist today, but to simplify our account here, we will pretend that they do exist. A value-safe type is any class, interface, or type parameter marked with the @ValueSafe annotation, or any subtype of a value-safe type.  If a value-safe class is marked final, it is in fact a value type.  All other value-safe classes must be abstract.  The non-static fields of a value class must be non-public and final, and all its constructors must be private. Under the above rules, a standard interface could be helpful to define value types like Complex.  Here is an example: @ValueSafe public interface ValueType extends java.io.Serializable {     // All methods listed here must get redefined.     // Definitions must be value-safe, which means     // they may depend on component values only.     List<? extends Object> asList();     int hashCode();     boolean equals(@ValueSafe Object c);     String toString(); } //@ValueSafe inherited from supertype: public final class Complex implements ValueType { … The main advantage of such a conventional interface is that (unlike an annotation) it is reified in the runtime type system.  It could appear as an element type or parameter bound, for facilities which are designed to work on value types only.  More broadly, it might assist the JVM to perform dynamic enforcement of the rules for value types. Besides types, the annotation @ValueSafe can mark fields, parameters, local variables, and methods.  (This is redundant when the type is also value-safe, but may be useful when the type is Object or another supertype of a value type.)  Working forward from these annotations, an expression E is defined as value-safe if it satisfies one or more of the following: The type of E is a value-safe type. E names a field, parameter, or local variable whose declaration is marked @ValueSafe. E is a call to a method whose declaration is marked @ValueSafe. E is an assignment to a value-safe variable, field reference, or array reference. E is a cast to a value-safe type from a value-safe expression. E is a conditional expression E0 ? E1 : E2, and both E1 and E2 are value-safe. Assignments to value-safe expressions and initializations of value-safe names must take their values from value-safe expressions. A value-safe expression may not be the subject of a value-unsafe operation.  In particular, it cannot be synchronized on, nor can it be compared with the “==” operator, not even with a null or with another value-safe type. In a program where all of these rules are followed, no value-type value will be subject to a value-unsafe operation.  Thus, the prime axiom of value types will be satisfied, that no two value type will be distinguishable as long as their component values are equal. More Code To illustrate these rules, here are some usage examples for Complex: Complex pi = Complex.valueOf(Math.PI, 0); Complex zero = pi.changeRe(0);  //zero = pi; zero.re = 0; ValueType vtype = pi; @SuppressWarnings("value-unsafe")   Object obj = pi; @ValueSafe Object obj2 = pi; obj2 = new Object();  // ok List<Complex> clist = new ArrayList<Complex>(); clist.add(pi);  // (ok assuming List.add param is @ValueSafe) List<ValueType> vlist = new ArrayList<ValueType>(); vlist.add(pi);  // (ok) List<Object> olist = new ArrayList<Object>(); olist.add(pi);  // warning: "value-unsafe" boolean z = pi.equals(zero); boolean z1 = (pi == zero);  // error: reference comparison on value type boolean z2 = (pi == null);  // error: reference comparison on value type boolean z3 = (pi == obj2);  // error: reference comparison on value type synchronized (pi) { }  // error: synch of value, unpredictable result synchronized (obj2) { }  // unpredictable result Complex qq = pi; qq = null;  // possible NPE; warning: “null-unsafe" qq = (Complex) obj;  // warning: “null-unsafe" qq = Complex.cast(obj);  // OK @SuppressWarnings("null-unsafe")   Complex empty = null;  // possible NPE qq = empty;  // possible NPE (null pollution) The Payoffs It follows from this that either the JVM or the java compiler can replace boxed value-type values with unboxed ones, without affecting normal computations.  Fields and variables of value types can be split into their unboxed components.  Non-static methods on value types can be transformed into static methods which take the components as value parameters. Some common questions arise around this point in any discussion of value types. Why burden the programmer with all these extra rules?  Why not detect programs automagically and perform unboxing transparently?  The answer is that it is easy to break the rules accidently unless they are agreed to by the programmer and enforced.  Automatic unboxing optimizations are tantalizing but (so far) unreachable ideal.  In the current state of the art, it is possible exhibit benchmarks in which automatic unboxing provides the desired effects, but it is not possible to provide a JVM with a performance model that assures the programmer when unboxing will occur.  This is why I’m writing this note, to enlist help from, and provide assurances to, the programmer.  Basically, I’m shooting for a good set of user-supplied “pragmas” to frame the desired optimization. Again, the important thing is that the unboxing must be done reliably, or else programmers will have no reason to work with the extra complexity of the value-safety rules.  There must be a reasonably stable performance model, wherein using a value type has approximately the same performance characteristics as writing the unboxed components as separate Java variables. There are some rough corners to the present scheme.  Since Java fields and array elements are initialized to null, value-type computations which incorporate uninitialized variables can produce null pointer exceptions.  One workaround for this is to require such variables to be null-tested, and the result replaced with a suitable all-zero value of the value type.  That is what the “cast” method does above. Generically typed APIs like List<T> will continue to manipulate boxed values always, at least until we figure out how to do reification of generic type instances.  Use of such APIs will elicit warnings until their type parameters (and/or relevant members) are annotated or typed as value-safe.  Retrofitting List<T> is likely to expose flaws in the present scheme, which we will need to engineer around.  Here are a couple of first approaches: public interface java.util.List<@ValueSafe T> extends Collection<T> { … public interface java.util.List<T extends Object|ValueType> extends Collection<T> { … (The second approach would require disjunctive types, in which value-safety is “contagious” from the constituent types.) With more transformations, the return value types of methods can also be unboxed.  This may require significant bytecode-level transformations, and would work best in the presence of a bytecode representation for multiple value groups, which I have proposed elsewhere under the title “Tuples in the VM”. But for starters, the JVM can apply this transformation under the covers, to internally compiled methods.  This would give a way to express multiple return values and structured return values, which is a significant pain-point for Java programmers, especially those who work with low-level structure types favored by modern vector and graphics processors.  The lack of multiple return values has a strong distorting effect on many Java APIs. Even if the JVM fails to unbox a value, there is still potential benefit to the value type.  Clustered computing systems something have copy operations (serialization or something similar) which apply implicitly to command operands.  When copying JVM objects, it is extremely helpful to know when an object’s identity is important or not.  If an object reference is a copied operand, the system may have to create a proxy handle which points back to the original object, so that side effects are visible.  Proxies must be managed carefully, and this can be expensive.  On the other hand, value types are exactly those types which a JVM can “copy and forget” with no downside. Array types are crucial to bulk data interfaces.  (As data sizes and rates increase, bulk data becomes more important than scalar data, so arrays are definitely accompanying us into the future of computing.)  Value types are very helpful for adding structure to bulk data, so a successful value type mechanism will make it easier for us to express richer forms of bulk data. Unboxing arrays (i.e., arrays containing unboxed values) will provide better cache and memory density, and more direct data movement within clustered or heterogeneous computing systems.  They require the deepest transformations, relative to today’s JVM.  There is an impedance mismatch between value-type arrays and Java’s covariant array typing, so compromises will need to be struck with existing Java semantics.  It is probably worth the effort, since arrays of unboxed value types are inherently more memory-efficient than standard Java arrays, which rely on dependent pointer chains. It may be sufficient to extend the “value-safe” concept to array declarations, and allow low-level transformations to change value-safe array declarations from the standard boxed form into an unboxed tuple-based form.  Such value-safe arrays would not be convertible to Object[] arrays.  Certain connection points, such as Arrays.copyOf and System.arraycopy might need additional input/output combinations, to allow smooth conversion between arrays with boxed and unboxed elements. Alternatively, the correct solution may have to wait until we have enough reification of generic types, and enough operator overloading, to enable an overhaul of Java arrays. Implicit Method Definitions The example of class Complex above may be unattractively complex.  I believe most or all of the elements of the example class are required by the logic of value types. If this is true, a programmer who writes a value type will have to write lots of error-prone boilerplate code.  On the other hand, I think nearly all of the code (except for the domain-specific parts like plus and minus) can be implicitly generated. Java has a rule for implicitly defining a class’s constructor, if no it defines no constructors explicitly.  Likewise, there are rules for providing default access modifiers for interface members.  Because of the highly regular structure of value types, it might be reasonable to perform similar implicit transformations on value types.  Here’s an example of a “highly implicit” definition of a complex number type: public class Complex implements ValueType {  // implicitly final     public double re, im;  // implicitly public final     //implicit methods are defined elementwise from te fields:     //  toString, asList, equals(2), hashCode, valueOf, cast     //optionally, explicit methods (plus, abs, etc.) would go here } In other words, with the right defaults, a simple value type definition can be a one-liner.  The observant reader will have noticed the similarities (and suitable differences) between the explicit methods above and the corresponding methods for List<T>. Another way to abbreviate such a class would be to make an annotation the primary trigger of the functionality, and to add the interface(s) implicitly: public @ValueType class Complex { … // implicitly final, implements ValueType (But to me it seems better to communicate the “magic” via an interface, even if it is rooted in an annotation.) Implicitly Defined Value Types So far we have been working with nominal value types, which is to say that the sequence of typed components is associated with a name and additional methods that convey the intention of the programmer.  A simple ordered pair of floating point numbers can be variously interpreted as (to name a few possibilities) a rectangular or polar complex number or Cartesian point.  The name and the methods convey the intended meaning. But what if we need a truly simple ordered pair of floating point numbers, without any further conceptual baggage?  Perhaps we are writing a method (like “divideAndRemainder”) which naturally returns a pair of numbers instead of a single number.  Wrapping the pair of numbers in a nominal type (like “QuotientAndRemainder”) makes as little sense as wrapping a single return value in a nominal type (like “Quotient”).  What we need here are structural value types commonly known as tuples. For the present discussion, let us assign a conventional, JVM-friendly name to tuples, roughly as follows: public class java.lang.tuple.$DD extends java.lang.tuple.Tuple {      double $1, $2; } Here the component names are fixed and all the required methods are defined implicitly.  The supertype is an abstract class which has suitable shared declarations.  The name itself mentions a JVM-style method parameter descriptor, which may be “cracked” to determine the number and types of the component fields. The odd thing about such a tuple type (and structural types in general) is it must be instantiated lazily, in response to linkage requests from one or more classes that need it.  The JVM and/or its class loaders must be prepared to spin a tuple type on demand, given a simple name reference, $xyz, where the xyz is cracked into a series of component types.  (Specifics of naming and name mangling need some tasteful engineering.) Tuples also seem to demand, even more than nominal types, some support from the language.  (This is probably because notations for non-nominal types work best as combinations of punctuation and type names, rather than named constructors like Function3 or Tuple2.)  At a minimum, languages with tuples usually (I think) have some sort of simple bracket notation for creating tuples, and a corresponding pattern-matching syntax (or “destructuring bind”) for taking tuples apart, at least when they are parameter lists.  Designing such a syntax is no simple thing, because it ought to play well with nominal value types, and also with pre-existing Java features, such as method parameter lists, implicit conversions, generic types, and reflection.  That is a task for another day. Other Use Cases Besides complex numbers and simple tuples there are many use cases for value types.  Many tuple-like types have natural value-type representations. These include rational numbers, point locations and pixel colors, and various kinds of dates and addresses. Other types have a variable-length ‘tail’ of internal values. The most common example of this is String, which is (mathematically) a sequence of UTF-16 character values. Similarly, bit vectors, multiple-precision numbers, and polynomials are composed of sequences of values. Such types include, in their representation, a reference to a variable-sized data structure (often an array) which (somehow) represents the sequence of values. The value type may also include ’header’ information. Variable-sized values often have a length distribution which favors short lengths. In that case, the design of the value type can make the first few values in the sequence be direct ’header’ fields of the value type. In the common case where the header is enough to represent the whole value, the tail can be a shared null value, or even just a null reference. Note that the tail need not be an immutable object, as long as the header type encapsulates it well enough. This is the case with String, where the tail is a mutable (but never mutated) character array. Field types and their order must be a globally visible part of the API.  The structure of the value type must be transparent enough to have a globally consistent unboxed representation, so that all callers and callees agree about the type and order of components  that appear as parameters, return types, and array elements.  This is a trade-off between efficiency and encapsulation, which is forced on us when we remove an indirection enjoyed by boxed representations.  A JVM-only transformation would not care about such visibility, but a bytecode transformation would need to take care that (say) the components of complex numbers would not get swapped after a redefinition of Complex and a partial recompile.  Perhaps constant pool references to value types need to declare the field order as assumed by each API user. This brings up the delicate status of private fields in a value type.  It must always be possible to load, store, and copy value types as coordinated groups, and the JVM performs those movements by moving individual scalar values between locals and stack.  If a component field is not public, what is to prevent hostile code from plucking it out of the tuple using a rogue aload or astore instruction?  Nothing but the verifier, so we may need to give it more smarts, so that it treats value types as inseparable groups of stack slots or locals (something like long or double). My initial thought was to make the fields always public, which would make the security problem moot.  But public is not always the right answer; consider the case of String, where the underlying mutable character array must be encapsulated to prevent security holes.  I believe we can win back both sides of the tradeoff, by training the verifier never to split up the components in an unboxed value.  Just as the verifier encapsulates the two halves of a 64-bit primitive, it can encapsulate the the header and body of an unboxed String, so that no code other than that of class String itself can take apart the values. Similar to String, we could build an efficient multi-precision decimal type along these lines: public final class DecimalValue extends ValueType {     protected final long header;     protected private final BigInteger digits;     public DecimalValue valueOf(int value, int scale) {         assert(scale >= 0);         return new DecimalValue(((long)value << 32) + scale, null);     }     public DecimalValue valueOf(long value, int scale) {         if (value == (int) value)             return valueOf((int)value, scale);         return new DecimalValue(-scale, new BigInteger(value));     } } Values of this type would be passed between methods as two machine words. Small values (those with a significand which fits into 32 bits) would be represented without any heap data at all, unless the DecimalValue itself were boxed. (Note the tension between encapsulation and unboxing in this case.  It would be better if the header and digits fields were private, but depending on where the unboxing information must “leak”, it is probably safer to make a public revelation of the internal structure.) Note that, although an array of Complex can be faked with a double-length array of double, there is no easy way to fake an array of unboxed DecimalValues.  (Either an array of boxed values or a transposed pair of homogeneous arrays would be reasonable fallbacks, in a current JVM.)  Getting the full benefit of unboxing and arrays will require some new JVM magic. Although the JVM emphasizes portability, system dependent code will benefit from using machine-level types larger than 64 bits.  For example, the back end of a linear algebra package might benefit from value types like Float4 which map to stock vector types.  This is probably only worthwhile if the unboxing arrays can be packed with such values. More Daydreams A more finely-divided design for dynamic enforcement of value safety could feature separate marker interfaces for each invariant.  An empty marker interface Unsynchronizable could cause suitable exceptions for monitor instructions on objects in marked classes.  More radically, a Interchangeable marker interface could cause JVM primitives that are sensitive to object identity to raise exceptions; the strangest result would be that the acmp instruction would have to be specified as raising an exception. @ValueSafe public interface ValueType extends java.io.Serializable,         Unsynchronizable, Interchangeable { … public class Complex implements ValueType {     // inherits Serializable, Unsynchronizable, Interchangeable, @ValueSafe     … It seems possible that Integer and the other wrapper types could be retro-fitted as value-safe types.  This is a major change, since wrapper objects would be unsynchronizable and their references interchangeable.  It is likely that code which violates value-safety for wrapper types exists but is uncommon.  It is less plausible to retro-fit String, since the prominent operation String.intern is often used with value-unsafe code. We should also reconsider the distinction between boxed and unboxed values in code.  The design presented above obscures that distinction.  As another thought experiment, we could imagine making a first class distinction in the type system between boxed and unboxed representations.  Since only primitive types are named with a lower-case initial letter, we could define that the capitalized version of a value type name always refers to the boxed representation, while the initial lower-case variant always refers to boxed.  For example: complex pi = complex.valueOf(Math.PI, 0); Complex boxPi = pi;  // convert to boxed myList.add(boxPi); complex z = myList.get(0);  // unbox Such a convention could perhaps absorb the current difference between int and Integer, double and Double. It might also allow the programmer to express a helpful distinction among array types. As said above, array types are crucial to bulk data interfaces, but are limited in the JVM.  Extending arrays beyond the present limitations is worth thinking about; for example, the Maxine JVM implementation has a hybrid object/array type.  Something like this which can also accommodate value type components seems worthwhile.  On the other hand, does it make sense for value types to contain short arrays?  And why should random-access arrays be the end of our design process, when bulk data is often sequentially accessed, and it might make sense to have heterogeneous streams of data as the natural “jumbo” data structure.  These considerations must wait for another day and another note. More Work It seems to me that a good sequence for introducing such value types would be as follows: Add the value-safety restrictions to an experimental version of javac. Code some sample applications with value types, including Complex and DecimalValue. Create an experimental JVM which internally unboxes value types but does not require new bytecodes to do so.  Ensure the feasibility of the performance model for the sample applications. Add tuple-like bytecodes (with or without generic type reification) to a major revision of the JVM, and teach the Java compiler to switch in the new bytecodes without code changes. A staggered roll-out like this would decouple language changes from bytecode changes, which is always a convenient thing. A similar investigation should be applied (concurrently) to array types.  In this case, it seems to me that the starting point is in the JVM: Add an experimental unboxing array data structure to a production JVM, perhaps along the lines of Maxine hybrids.  No bytecode or language support is required at first; everything can be done with encapsulated unsafe operations and/or method handles. Create an experimental JVM which internally unboxes value types but does not require new bytecodes to do so.  Ensure the feasibility of the performance model for the sample applications. Add tuple-like bytecodes (with or without generic type reification) to a major revision of the JVM, and teach the Java compiler to switch in the new bytecodes without code changes. That’s enough musing me for now.  Back to work!

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  • heartbeat: Bad nodename in /etc/ha.d//haresources [node1]

    - by Richard
    I'm trying to start heartbeat on Ubuntu 10.04 with service heartbeat start, but getting the following errors: heartbeat[24829]: 2011/11/22_19:31:07 ERROR: Bad nodename in /etc/ha.d//haresources [node1] heartbeat[24829]: 2011/11/22_19:31:07 ERROR: Configuration error, heartbeat not started. On on server uname -n produces loadb1, on the second server uname -n produces loadb2. The two servers can ping each other okay with those names. This is /etc/ha.d/ha.cnf on both servers: debugfile /var/log/ha-debug logfile /var/log/ha-log logfacility local0 keepalive 2 deadtime 10 udpport 694 bcast eth1 ucast eth0 my.external.ip ucast eth0 my.external.ip ucast eth1 10.0.0.5 ucast eth1 10.0.0.6 #udp eth0 node loadb1 node loadb2 auto_failback off And this is /etc/ha.d/haresources on both servers: node1 IPaddr::46.20.121.113 httpd smb dhcpd Authkeys is also set up. What am I doing wrong? The part where I'm least clear is the ucast/bcast lines.

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  • HP Network Utility Error

    - by William Ricci
    Using the HP Network Utility to team 2 ports on Windows 2008 R2 Standard results in this error:----- An error occurred when making a call into the operating system. Happens on either of two cards that are installed. This happened before and after upgrading to PSP 9.10. Uninstalled the HP Network Configuration Utility and re-installed version 10.65.0.6. Updated NIC drivers. NC382i DP - HP Broadcom 1Gb Multifunction Driver 7.4.23.0 (from 6.2.9.0) NC365T - Intel E1R 11.14.80.0 (from 11.14.49.0)

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  • MDaemon vs Exchange (2007-2010). Which one should we choose ?

    - by Deniz
    We are at the verge of a mail server decision. We do currently use 2 mail servers : MDaemon 10 and Exchange 2003. We are planning to use a company and customer wide one point solution. Our main candidates are MDaemon 11 and Exchange 2007 or 2010. We would like to learn other users experiences on those solutions. The server-side experiences, the user-side experiences, feature set, TCO, support options etc. And if there were other solutions (like MDaemon 11 + Exchange or anything else) what would you suggest ?

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  • Local Flash in Chrome pepper player won't link to internet

    - by No one in particluar
    I have a local .swf file in a local .html file. The flash file opens a popup window when a link is clicked. In Chrome, when I open the html file and click the button, nothing happens. Then when I go to about:plugins and disable the top Flash player (the pepper one) then try refresh and try clicking the button again, nothing happens. Then when I go to http://www.macromedia.com/support/documentation/en/flashplayer/help/settings_manager04.html and add the the folder the files are stored in to the list and refresh the page and click the button again, it opens the popup. When I re-enable the pepper flash player, and re-add the folder to the allowed list in flash (it's gone from the list now that I changed players), refresh the page and click the button again, it does nothing. I don't know why it won't open with the pepper player. I'm using Windows 7, Chrome 22.0.1229.94 m, Pepper Flash player 11.4.31.110, and regular Flash Player 11,4,402,287.

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  • OpenSolaris Dead / Alive?

    - by Walter White
    Hi all, I have used Open Solaris in the past and really liked it, minus the lack of support for a few applications I use such as UFraw, Hugin, and wacom. I can compile from source, but where is the fun in that. It seems the release dates for the next Open Solaris keep getting pushed back and the release that was scheduled to happen quietly got pulled from their site. So, they're no longer saying development for 10.03 has already begun because it has come and gone and there is no release. Walter

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  • How is htop "Swp" calculated?

    - by Thomas
    When I run htop (on OS X 10.6.8), I see something like this : 1 [||||||| 20.0%] Tasks: 70 total, 0 running 2 [||| 7.2%] Load average: 1.11 0.79 0.64 3 [|||||||||||||||||||||||||||81.3%] Uptime: 00:30:42 4 [|| 5.8%] Mem[|||||||||||||||||||||3872/4096MB] Swp[ 0/0MB] PID USER PRI NI VIRT RES SHR S CPU% MEM% TIME+ Command 284 501 57 0 15.3G 1064M 0 S 0.0 6.5 0:01.26 /Applications/Firefox.app/Contents/MacOS/firefox -psn_0_90134 437 501 57 0 14.8G 785M 0 S 0.0 4.8 0:00.18 /Applications/Thunderbird.app/Contents/MacOS/thunderbird -psn_0_114716 428 501 63 0 12.8G 351M 0 S 1.0 2.1 0:00.51 /Applications/Firefox.app/Contents/MacOS/plugin-container.app/Contents/MacOS/ 696 501 63 0 11.7G 175M 0 S 0.0 1.1 0:00.02 /System/Library/Frameworks/QuickLook.framework/Resources/quicklookd.app/Conte 38 0 33 0 11.1G 422M 0 S 0.0 2.6 0:00.59 /System/Library/Frameworks/CoreServices.framework/Frameworks/Metadata.framewo 183 501 48 0 10.9G 137M 0 S 0.0 0.8 0:00.03 /System/Library/CoreServices/Finder.app/Contents/MacOS/Finder How can I have Processes using Gigabytes of VIRT memory and still 0MB of Swap used ?

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  • SUSE 12.1 Apache startup after oci8 installation

    - by DKSan
    I have got a virtual server running opensuse 11.4 with apache, php, oracle instantclient, and oci installed through pecl. The steps it took for me to have it up and running on 11.4 were: # Install instantclient rpm -Uvh oracle-instantclient11.2-basic-11.2.0.2.0.x86_64.rpm rpm -Uvh oracle-instantclient11.2-devel-11.2.0.2.0.x86_64.rpm # Install OCI8 through pecl pecl install oci8 # add oci8 to modules vi /etc/php5/conf.d/oci8.ini extension=oci8.so # add LD_LIBRARY_PATH to apache vi /etc/sysconfig/apache2 # add to bottom of script export LD_LIBRARY_PATH="/usr/lib/oracle/11.2/client64/lib" # restart Apache /etc/init.d/apache2 restart Celebrating the same procedure on a fresh installation of OpenSUSE 12.1 results in apache throwing the following message at startup: PHP Warning: PHP Startup: Unable to load dynamic library '/usr/lib64/php5/extensions/oci8.so' - libnnz11.so: cannot open shared object file: No such file or directory in Unknown on line 0 I can't get any explanation, why it is working for 11.4 and in 12.1 it stops working. Can someone please point me in the right direction..

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  • DHCP "no answer" on CentOS 6.4

    - by Kev
    I installed a DHCP server (yum install dhcp) and this is my conf: # create new # specify domain name option domain-name "mydomain.name"; # specify DNS's hostname or IP address option domain-name-servers 10.0.1.1, 10.0.1.2; option ntp-servers 10.0.1.1, 10.0.1.2; allow unknown-clients; # default lease time default-lease-time 2628000; # max lease time max-lease-time 2628000; # about a month # this DHCP server to be declared valid authoritative; # specify network address and subnet mask subnet 10.0.0.0 netmask 255.0.0.0 { # specify the range of lease IP address range dynamic-bootp 10.0.2.1 10.0.2.50; # specify broadcast address option broadcast-address 10.255.255.255; # specify default gateway option routers 10.0.0.1; allow unknown-clients; } service dhcp start reports [ OK ]. Yet, if I disable my other DHCP server (Win2k3) and get a client to try renewing its IP lease, it times out. So I installed dhcping. No matter what options I try, including directing dhcping at my server, adding a client address in the range, adding my hardware address, it replies 'no answer'. I'm also trying -i since that seems to be more akin to what a WinXP client would try to do, based on /var/log/messages. It logs the attempts (from dhcping here) as: Oct 24 18:55:13 newdc dhcpd: DHCPINFORM from 10.0.2.15 via eth0:4 Oct 24 18:55:13 newdc dhcpd: DHCPACK to 10.0.2.15 (00:11:25:66:4e:7f) via eth0:4 Oct 24 18:55:13 newdc dhcpd: DHCPINFORM from 10.0.2.15 via eth0:3 Oct 24 18:55:13 newdc dhcpd: DHCPACK to 10.0.2.15 (00:11:25:66:4e:7f) via eth0:3 Oct 24 18:55:13 newdc dhcpd: DHCPINFORM from 10.0.2.15 via eth0 Oct 24 18:55:13 newdc dhcpd: DHCPACK to 10.0.2.15 (00:11:25:66:4e:7f) via eth0 The :3 and :4 are because I have a few extra Host(A) records for this server so it responds on more than one IP for our intranet app. No answer? It sounds like it should be getting three answers...no? (And if that's the problem, how do I limit the DHCP service to replying from eth0?)

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  • GConf error and gnome does not load properly in RHEL 5.3

    - by Tim
    Hello, I am using Red Hat Enterprise Linux 5.3 . I created a user oracle on the system, using the following command useradd -g oinstall -G dba,oper -d /home/oracle oracle Now, when i try to login as the user oracle, GNOME does not load properly and i get popup box error message like the following GConf error:Failed to contact configuration server;some possible causes are that you need to enable TCP/IP for ORBit,or your have NFS locks due to a system crash.(Details-/:IOR file'/tmp/gcofd-cheetahman/tock/ior' not opened successfully,no gconfd located:Permission denied 2: IOR file /tmp/gconfd-cheetahman/lock/ior not opened succesfully no gconfd located: Permission denied) Any way to fix this ? Thank You

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  • 5.5.0 smtp;554 transaction failed spam message not queued

    - by Miguel
    Some users are trying to send email to certain domains using Exchange Server 2003, but the message is always is rejected and the following message is shown: 5.5.0 smtp;554 Transaction Failed Spam Message not queued The IP is not in a black list (checked using http://whatismyipaddress.com/blacklist-check and is clean - not listed). The emails were checked using using smtpdiag ("a troubleshooting tool designed to work directly on a Windows server with IIS/SMTP service enabled or with Exchange Server installed") and the connection using port 25 is ok. Also, an nslookup with set type=ptr shows (names and IP changed, "" means I typed something): C:\Documents and Settings\administrator>nslookup Default Server: publicdns.isp.net Address: 10.10.10.10 > server publicdns.isp.net Default Server: publicdns.isp.net Address: 10.10.10.10 > set type=ptr >mydomain.com Server: publicdns.isp.net Address: 10.10.10.10 mydomain.com primary name server = publicdns.isp.net responsible mail addr = root.isp.net serial = 2011061301 refresh = 10800 (3 hours) retry = 3600 (1 hour) expire = 604800 (7 days) default TTL = 86400 (1 day) > 20.21.22.23 Server: publicdns.isp.net Address: 10.10.10.10 23.22.21.20.in-addr.arpa name = mail.mydomain.com 20.21.in-addr.arpa nameserver = publicdns.isp.net 20.21.in-addr.arpa nameserver = publicdns2.isp.net publicdns2.isp.net internet address = 10.10.10.11 publicdns.isp.net internet address = 10.10.10.10 Server: publicdns.isp.net Address: 10.10.10.10 23.22.21.20.in-addr.arpa name = mail.mydomain.com 20.21.in-addr.arpa nameserver = publicdns.isp.net 20.21.in-addr.arpa nameserver = publicdns2.isp.net publicdns2.isp.net internet address = 10.10.10.11 publicdns.isp.net internet address = 10.10.10.10 > set type=mx > mydomain.com Server: publicdns.isp.net Address: 10.10.10.10 mydomain.com MX preference = 10, mail exchanger = mail.mydomain.com mydomain.com nameserver = publicdns.isp.net mydomain.com nameserver = publicdns2.isp.net mail.mydomain.com internet address = 20.21.22.23 publicdns2.isp.net internet address = 10.10.10.11 publicdns.isp.net internet address = 10.10.10.10 > set type=a > mydomain.com Server: publicdns.isp.net Address: 10.10.10.10 Nombre: mydomain.com Address: 20.21.22.23 When I test the spf record with http://www.mxtoolbox.com it shows: TXT mydomain.com 24 hrs v=spf1 a mx ptr ip4:20.21.22.23 mx:mail.mydomain.com -all Any clues of what's happening here?

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  • Netbook performance - 1.33 GHz vs 1.6/1.66 GHz Atom

    - by Imran
    All new 11" netbooks seem to carry 1.33 GHz Atom Z520 CPU instead of 1.6/1.66 GHz Atom N270/N280. The screen resolution of 11" netbooks make them very appealing, but I'm a bit concerned about their performance as they carry a slower CPU than the 1.6GHz Atom, which isn't a great performer in the first place. Is there any significant difference in performance between 1.33 GHz and 1.6/1.66 GHz Atom processors in day to day usage? Are any of those fast enough to decode 720p x264 video? (When paired with typical Intel GMA platform and software decoder like ffdshow/CoreAVC of course, not with Nvidia Ion platform)

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  • Export mysql database tables to php code to create same tables in other database?

    - by chefnelone
    How do I Export mysql database tables to php code so that it allows me to create and populate same tables in other database? I have a local database, I exported to sql syntax, then I get something like: CREATE TABLE `boletinSuscritos` ( `id` int(11) NOT NULL AUTO_INCREMENT, `name` varchar(120) NOT NULL, `email` varchar(120) NOT NULL, `date` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP, PRIMARY KEY (`id`) ) ENGINE=MyISAM DEFAULT CHARSET=utf8 AUTO_INCREMENT=3 ; INSERT INTO `boletinSuscritos` VALUES(1, 'walter', '[email protected]', '2010-03-24 12:53:12'); INSERT INTO `boletinSuscritos` VALUES(2, 'Paco', '[email protected]', '2010-03-24 12:56:56'); but I need it to be: (Is there any way to export the tables in this way) $sql = "CREATE TABLE boletinSuscritos ( id int(11) NOT NULL AUTO_INCREMENT, name varchar(120) NOT NULL, email varchar(120) NOT NULL, date timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP, PRIMARY KEY ( id ) ) ENGINE=MyISAM DEFAULT CHARSET=utf8 AUTO_INCREMENT=3 )"; mysql_query($sql,$conexion); mysql_query("INSERT INTO boletinSuscritos VALUES(1, 'walter', '[email protected]', '2010-03-24 12:53:12')"); mysql_query("INSERT INTO boletinSuscritos VALUES(2, 'Paco', '[email protected]', '2010-03-24 12:56:56')");

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  • Error codes 80070490 and 8024200D in Windows Update

    - by Sammy
    How do get past these stupid errors? The way I have set things up is that Windows Update tells me when there are new updates available and then I review them before installing them. Yesterday it told me that there were 11 new updates. So I reviewed them and I saw that about half of them were security updates for Vista x64 and .NET Framework 2.0 SP2, and half of them were just regular updates for Vista x64. I checked them all and hit the Install button. It seemed to work at first, updates were being downloaded and installed, but then at update 11 of 11 total it got stuck and gave me the two error codes you see in the title. Here are some screenshots to give you an idea of what it looks like. This is what it looks like when it presents the updates to me. This is how it looks like when the installation fails. I'm not sure if you're gonna see this very well but these are the updates it's trying to install. Update: This is on Windows Vista Ultimate 64-bit with integrated SP2, installed only two weeks ago on 2012-10-02. Aside from this, the install is working flawlessly. I have not done any major changes to the system like installing new devices or drivers. What I have tried so far: - I tried installing the System Update Readiness Tool (the correct one for Vista x64) from Microsoft. This did not solve the issue. Microsoft resource links: Solutions to 80070490 Windows Update error 80070490 System Update Readiness Tool fixes Windows Update errors in Windows 7, Windows Vista, Windows Server 2008 R2, and Windows Server 2008 Solutions to 8024200D: Windows Update error 8024200d Essentially both solutions tell you to install the System Update Readiness Tool for your system. As I have done so and it didn't solve the problem the next step would be to try to repair Windows. Before I do that, is there anything else I can try? Microsoft automatic troubleshooter If I click the automatic troubleshooter link available on the solution web page above it directs me to download a file called windowsupdate.diagcab. But after download this file is not associated to any Windows program. Is this the so called Microsoft Fix It program? It doesn't have its icon, it's just blank file. Does it need to be associated? And to what Windows program?

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