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

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Top 5 Answer for What's the simplest way to print a Java array?

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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.


  • Simple Array:

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


    [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)); 


    [[John, Mary], [Alice, Bob]] 
  • double Array:

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


    [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)); 


    [7, 9, 5, 1, 3 ] 
vote vote


Always check the standard libraries first.

import java.util.Arrays; 

Then try:


or if your array contains other arrays as elements:

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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 ) ); 
vote vote


In JDK1.8 you can use aggregate operations and a lambda expression:

String[] strArray = new String[] {"John", "Mary", "Bob"};  // #1 Arrays.asList(strArray).stream().forEach(s -> System.out.println(s));  // #2 Stream.of(strArray).forEach(System.out::println);  // #3 Arrays.stream(strArray).forEach(System.out::println);  /* output: John Mary Bob */ 
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Starting with Java 8, one could also take advantage of the join() method provided by the String class to print out array elements, without the brackets, and separated by a delimiter of choice (which is the space character for the example shown below):

String[] greeting = {"Hey", "there", "amigo!"}; String delimiter = " "; String.join(delimiter, greeting)  

The output will be "Hey there amigo!".

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