I have to read values from SQLite database but getting null pointer exception when I execute private final String DB_NAME = "UserDb"; private final String TABLE_NAMES = "tbluser"; SQLiteDatabase sampleDB; Cursor c=null; c= sampleDB.rawQuery("SELECT * from " +TABLE_NAMES+" where did='"+deviceDec+"' ", null); Please suggest me why I am getting the exception because at one function it is running but in other it is not. and the deviceDec value also i am getting I have checked in Log