Java
Java (not to be confused with JavaScript or JScript or JS) is a general-purpose object-oriented programming language designed to be used in conjunction with the Java Virtual Machine (JVM). "Java platform" is the name for a computing system that has installed tools for developing and running Java programs. Use this tag for questions referring to the Java programming language or Java platform tools.
56
votes
30
answers
2K
views
Difference between StringBuilder and StringBuffer
What is the main difference between StringBuffer and StringBuilder? Is there any performance issues when decid
60
votes
30
answers
1.3K
views
Why use getters and setters/accessors?
What's the advantage of using getters and setters - that only get and set - instead of simply using publi
64
votes
30
answers
832
views
How can I avoid Java code in JSP files, using JSP 2?
I'm new to Java EE and I know that something like the following three lines <%= x+1 %> <%= reque
51
votes
30
answers
700
views
Sort a Map<Key, Value> by values
I am relatively new to Java, and often find that I need to sort a Map<Key, Value> on the values. Since
51
votes
30
answers
1.1K
views
How to split a string in Java
I have a string, "004-034556", that I want to split into two strings: string1="004"; string2="034556"; That
54
votes
15
answers
2.8K
views
Why does this code using random strings print "hello world"?
The following print statement would print "hello world". Could anyone explain this? System.out.println(random
63
votes
30
answers
2.2K
views
How to generate a random alpha-numeric string
I've been looking for a simple Java algorithm to generate a pseudo-random alpha-numeric string. In my si
66
votes
25
answers
563
views
Does Java support default parameter values?
I came across some Java code that had the following structure: public MyParameterizedFunction(String param1,
57
votes
27
answers
1.4K
views
Java inner class and static nested class
What is the main difference between an inner class and a static nested class in Java? Does design / implementa
49
votes
14
answers
1.7K
views
Comparing Java enum members: == or equals()?
I know that Java enums are compiled to classes with private constructors and a bunch of public static members.
49
votes
30
answers
2.8K
views
How do I break out of nested loops in Java?
I've got a nested loop construct like this: for (Type type : types) { for (Type t : types2) {
66
votes
11
answers
907
views
How to use java.net.URLConnection to fire and handle HTTP requests
Use of java.net.URLConnection is asked about pretty often here, and the Oracle tutorial is too concise about i
62
votes
23
answers
406
views
What is a JavaBean exactly?
I understood, I think, that a "Bean" is a Java class with properties and getters/setters. As much as I underst
63
votes
30
answers
1.6K
views
How do you assert that a certain exception is thrown in JUnit 4 tests?
How can I use JUnit4 idiomatically to test that some code throws an exception? While I can certainly do somet
59
votes
30
answers
1.1K
views
What's the simplest way to print a Java array?
In Java, arrays don't override toString(), so if you try to print one directly, you get the className + &
48
votes
30
answers
2.7K
views
How to get an enum value from a string value in Java
Say I have an enum which is just public enum Blah { A, B, C, D } and I would like to find the enum value
57
votes
30
answers
1.8K
views
"implements Runnable" vs "extends Thread" in Java
From what time I've spent with threads in Java, I've found these two ways to write threads: With imp
65
votes
28
answers
2.1K
views
54
votes
29
answers
2.6K
views
What's the difference between @Component, @Repository & @Service annotations in Spring?
Can @Component, @Repository and @Service annotations be used interchangeably in Spring or do they provide any
53
votes
22
answers
1.2K
views
What is reflection and why is it useful?
What is reflection, and why is it useful? I'm particularly interested in Java, but I assume the principle
