How do I pass an array to a method?

Question

Hey,

I have not been able to find a proper answer on any forums about this.
But how exactly do I pass an array to a class constructor?

public class TestArray {
   String name;
   String[] array;

   public TestArray(String name, String[] anArray){
          this.name = name;
          int len = anArray.length;
          this.array = new String[len];
          for (int i = 0; i < len; i++)
          {
              this.array[i] = new String(anArray[i]);
          }
   }

   public static void main(String[] args){
        String[] anArray = new String[2];
        anArray[0] = new String("Test");
        anArray[1] = new String("Test2");
        TestArray work = new TestArray("Jordan", anArray); // How to pass the array?
   }
}

Answer 1

Your code will work, minus the question mark in the last line (edit - this was removed by the editor).

Your braces are also off - move the main function inside the class (you have one too many closing braces after the TestArray constructor).

Edit 2 - now that your question has been edited to fix your errors, it should work as expected. I am not sure if this is the best practice for SO, but that's a discussion for meta.

Answer 2

Exactly like you wrote...

Update:

Maybe you got a compiling error, if so, you placed a closing braces (}) too much in your code. I removed it by formatting your code. Maybe this was the problem...

Answer 3

Arrays are objects - so are passed them by reference. And you don't need to make copies yourself. If you really feel you have to copy then better use System.arraycopy.

Answer 4

public static void main(String[] args){
    String[] anArray = new String[2];
    anArray[0] = new String("Test");
    anArray[1] = new String("Test2");
    TestArray work = new TestArray("Jordan", anArray);
}

This will work perfectly, although there is a shorter way to initialize anArray:

public static void main(String[] args){
    String[] anArray = new String[] { "Test", "Test2" };
    TestArray work = new TestArray("Jordan", anArray);
}

Which in turn can be shortened to:

public static void main(String[] args){
    TestArray work = new TestArray("Jordan", new String[] { "Test", "Test2" });
}

By the way, String objects are immutable, so you don't have to initialize new strings every time. They can be used directly like this.

Last tip: Arrays.copyOf(anArray, anArray.length) also returns a copy of the array, without the the for-loop.