In attempts of 100% code coverage, I came across a situation where I need to unit test block of code that catches an InterruptedException. How does one correctly unit test this? (JUnit 4 syntax please) Answer Right before invoking addMessage(), call Thread.currentThread().interrupt(). This will set the “…
Immutable array in Java
Is there an immutable alternative to the primitive arrays in Java? Making a primitive array final doesn’t actually prevent one from doing something like I want the elements of the array to be unchangeable. Answer Not with primitive arrays. You’ll need to use a List or some other data structure:
How to find out what algorithm [ encryption ] are supported by my JVM?
I am using Jasypt for encryption. This is my code: Uncomment the setAlgorithm line and it will throw an exception org.jasypt.exceptions.EncryptionOperationNotPossibleException: Encryption raised an excep tion. A possible cause is you are using strong encryption algorithms and you have not installed the Java C…
How do I allow the user to easily choose how much memory to allocate in a Java Swing app?
We have a Swing app that processes relatively large amounts of data. For instance we currently process CSV files with millions of rows of data. For the reasons of performance and simplicity we just keep all of the data in memory. However different users will have different amounts of data they need to process…
Java’s enum… Where are they created?
Since enum in C# are on the stack, I was wondering where enum, in Java, where created. On the stack? On the heap? In some mysterious other place? Enumeration in C# are more primitive than those in Java, this might explain why they are created on the stack… Where are they? I can’t find them! Thanks…
Circular dependency in Java constructors
I have the following classes. and As can be clearly seen, there is a circular dependency between the classes. if I try to run class A, I eventually get a StackOverflowError. If a dependency graph is created, where nodes are classes, then this dependency can be easily identified (at least for graphs with few n…
Switch between a TextView and EditText
Is this possible to interchange a TextView and an EditText. Like display the text when needed, but allow editing when needed. Is there a method (as in NON-XML) way of editing a TextView or non-editing a EditText? Answer Is this possible to interchange a TextView and an EditText. Put both in your layout in the…
How to create a directory in Java?
How do I create Directory/folder? Once I have tested System.getProperty(“user.home”); I have to create a directory (directory name “new folder” ) if and only if new folder does not exist. Answer After ~7 year, I will update it to better approach which is suggested by Bozho.
Can java run a compiled scala code?
Can command java run a compiled scala code? If so, why do we have an exclusive command scala?
@override annotation in JDK 1.6
I’m using JDK1.6. When I implement an interface and in the implementing class, if I give @override before my function names, Eclipse throws an compilation error. i.e. below code is wrong according to Eclipse. If I remove @Override annotation, then the code compiles fine. Does it mean that JDK1.6 does no…