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 ]