What's the simplest way to print a Java array?

Since Java 5 you can use Arrays.toString(arr) or Arrays.deepToString(arr) for arrays within arrays. Note that the Object[] version calls .toString() on each object in the array. The output is even decorated in the exact way you're asking.

Examples:

• Simple Array:

  String[] array = new String[] {"John", "Mary", "Bob"};System.out.println(Arrays.toString(array));

  Output:

  [John, Mary, Bob]

• Nested Array:

  String[][] deepArray = new String[][] {{"John", "Mary"}, {"Alice", "Bob"}};System.out.println(Arrays.toString(deepArray));//output: [[Ljava.lang.String;@106d69c, [Ljava.lang.String;@52e922]System.out.println(Arrays.deepToString(deepArray));

  Output:

  [[John, Mary], [Alice, Bob]]

• double Array:

  double[] doubleArray = { 7.0, 9.0, 5.0, 1.0, 3.0 };System.out.println(Arrays.toString(doubleArray));

  Output:

  [7.0, 9.0, 5.0, 1.0, 3.0 ]

• int Array:

  int[] intArray = { 7, 9, 5, 1, 3 };System.out.println(Arrays.toString(intArray));

  Output:

  [7, 9, 5, 1, 3 ]

Always check the standard libraries first.

import java.util.Arrays;

Then try:

System.out.println(Arrays.toString(array));

or if your array contains other arrays as elements:

System.out.println(Arrays.deepToString(array));

This is nice to know, however, as for "always check the standard libraries first" I'd never have stumbled upon the trick of Arrays.toString( myarray )

--since I was concentrating on the type of myarray to see how to do this. I didn't want to have to iterate through the thing: I wanted an easy call to make it come out similar to what I see in the Eclipse debugger and myarray.toString() just wasn't doing it.

import java.util.Arrays;...System.out.println( Arrays.toString( myarray ) );