Trouble understanding static

Question

Like the topic says, I do use it (actually I have to for the GUIs or they don't compile), but I really don't understand too much about them (what they allow, what they limit) and the definition on java.sun is not very clear to me. Could someone please give me a brief explanation on this subject and maybe an example?

Answer 1

public class Test {
    private String myName = "My name is . . .!";  //private variable of class Test
  public static void main(String[] argv)   //is static because the runtime environment needs to call this first, before making any objects, so it's not essential for your class, just gives you a way of running your code from within your class itself
    String theNameMainGets = "";  //main will receive the name in this
    Test testThis = new Test();  //make an instance without a name
    Test testThisWithAName = new Test("nogoodatcoding"); //pass a cool name to the constructor :D
    //theNameMainGets = whatIsMyName(); //will not work since main is static, so even though it is part of the same class, it cannot call a non-static member, whatIsMyName, because a copy of that is with every instance, and when main calls it, the instance may not exist
    theNameMainGets = testThis.whatIsMyName(); //correct way to access the non-static member, by creating an instance and then using that to access it
    System.out.println(theNameMainGets);
    theNameMainGets = testThisWithAName.whatIsMyName();
    System.out.println(theNameMainGets);
    //note, you can't say, testThis.myName; since myName is private to testThis.
Test()
      myName = "No one named me";
Test( String newName )
      myName = newName;
    public String whatIsMyName()
      return myName;
}Hope this helps