Java weirdness

One does not equal one

System.out.println(new Integer(1) == new Integer(1)); //prints false

Explanation: the equality operator checks if you are comparing the same objects not the same value.

Same strings aren't always the same

System.out.println("a" == "a"); //true
String a = "a";
String b = "a";
System.out.println(a == b); //true
String c = new String("a");
String d = "a";
System.out.println(c == d); //false

Strongly typed language, except when it's not

Integer foo = 5;
int bar = 5;
System.out.println(foo == bar); //true

Interesting list to array conversion API

List<String> stringList = new ArrayList<String>();
stringList.add("Lorem");
stringList.add("Ipsum");
String[] stringArray = stringList.toArray(new String[stringList.size()]);