C# equivalent to Java’s charAt()?
You can index into a string in C# like an array, and you get the character at that index. Example: In Java, you would say In C#, you would say
java
Java switch statement: Constant expression required, but it IS constant
I understand that the compiler needs the expression to be known at compile time to compile a switch, but why isn’t Foo.BA_ constant? While they are constant from the perspective of any code that executes after the fields have been initialized, they are not a compile time constant in the sense required by the JLS; … Read more
Change the size of a JTextField inside a JBorderLayout
From the api on GridLayout: The container is divided into equal-sized rectangles, and one component is placed in each rectangle. Try using FlowLayout or GridBagLayout for your set size to be meaningful. Also, @Serplat is correct. You need to use setPreferredSize( Dimension ) instead of setSize( int, int ).
‘No JUnit tests found’ in Eclipse
Right Click on Project > Properties > Java Build Path > Add the Test folder as source folder. All source folders including Test Classes need to be in Eclipse Java Build Path. So that the sources such as main and test classes can be compiled into the build directory (Eclipse default folder is bin).
How to map a composite key with JPA and Hibernate?
To map a composite key, you can use the EmbeddedId or the IdClass annotations. I know this question is not strictly about JPA but the rules defined by the specification also applies. So here they are: 2.1.4 Primary Keys and Entity Identity … A composite primary key must correspond to either a single persistent field or property or to a … Read more
How do you set one array’s values to another array’s values in Java?
You may want to use clone: or use arraycopy(Object source, int sourcePosition, Object destination, int destinationPosition, int numberOfElements)
How to Set the Background Color of a JButton on the Mac OS
Have you tried setting JButton.setOpaque(true)?
How to break out or exit a method in Java?
Use the return keyword to exit from a method. From the Java Tutorial that I linked to above: Any method declared void doesn’t return a value. It does not need to contain a return statement, but it may do so. In such a case, a return statement can be used to branch out of a control flow … Read more
Eclipse Problems View not showing Errors anymore
I had same problem and randomly did such things as (several times): 1) Project->Clean…,2) close and open Eclipse again,3) Run As… And it started to work again, without changing configuration.
How do I initialize a byte array in Java?
You can use an utility function to convert from the familiar hexa string to a byte[]. When used to define a final static constant, the performance cost is irrelevant. Since Java 17 There’s now java.util.HexFormat which lets you do This utility class lets you specify a format which is handy if you find other formats easier to read or when … Read more