Java String Array Example

Konstantina DimtsaJanuary 15th, 2014Last Updated: November 9th, 2023

4 489 3 minutes read

Last updated Jan. 14, 2019

In this example we will show how to declare and populate a Java String Array as well as how to iterate through all its elements.

1. Example of Java String Array

Create a java class named JavaStringArrayExample.java with the following code:

JavaStringArrayExample.java

package com.javacodegeeks.javabasics.stringarray;

public class JavaStringArrayExample {

 public static void main(String args[]) {

 // declare a string array with initial size
 String[] schoolbag = new String[4];

 // add elements to the array
 schoolbag[0] = "Books";
 schoolbag[1] = "Pens";
 schoolbag[2] = "Pencils";
 schoolbag[3] = "Notebooks";

 // this will cause ArrayIndexOutOfBoundsException
 // schoolbag[4] = "Notebooks";
 }
}

Let’s give a short explanation of the above code. First, we declare a string array with an initial size of 4 elements and then add 4 elements. If you try to add one more element, you will have java.lang.ArrayIndexOutOfBoundsException, as the capacity of the array is fixed and cannot be resized once created. If you want a dynamically sized array where you can add and remove the objects and the size is adjusted accordingly, you should use an ArrayList. You can have a look at How to use ArrayList example.

package com.javacodegeeks.javabasics.stringarray;

public class JavaStringArrayExample {

 public static void main(String args[]) {
 // declare a string array with no initial size
 // String[] schoolbag;

 // declare string array and initialize with values in one step
 String[] schoolbag = { "Books", "Pens", "Pencils", "Notebooks" };

 // print the third element of the string array
 System.out.println("The third element is: " + schoolbag2[2]);
 }
}

Next, we defined another string array named schoolbag2 as it is more common to declare and populate a string array in one step.

Output:

The third element is: Pencils

Now, we will show two ways of iterating through all the elements of the array.

The first one is a more “traditional way”, by using the standard for loop mechanism and the size of the array.

package com.javacodegeeks.javabasics.stringarray;

public class JavaStringArrayExample {

 public static void main(String args[]) {

  String[] schoolbag = { "Books", "Pens", "Pencils", "Notebooks" };

  // iterate all the elements of the array
  int size = schoolbag.length;
  System.out.println("The size of array is: " + size);

  for (int i = 0; i < size; i++) {
   System.out.println("Index[" + i + "] = " + schoolbag[i]);
  }
 }
}

Output:

The size of array is: 4
Index[0] = Books
Index[1] = Pens
Index[2] = Pencils
Index[3] = Notebooks

The second way uses the enhanced for loop example, which was introduced in Java 5.

package com.javacodegeeks.javabasics.stringarray;

public class JavaStringArrayExample {

 public static void main(String args[]) {

  String[] schoolbag = { "Books", "Pens", "Pencils", "Notebooks" };

  // iteration provided by Java 5 or later
  for (String str : schoolbag) {
   System.out.println(str);
 }
}

Output:

Books
Pens
Pencils
Notebooks

Let’s now test if a string array contains a value.

package com.javacodegeeks.javabasics.stringarray;

public class JavaStringArrayExample {

 public static void main(String args[]) {

  String[] schoolbag = { "Books", "Pens", "Pencils", "Notebooks" };

  String findString = "Pens";
  boolean found = false;
  for (String element:schoolbag) {
      if (element.equals(findString)) {
          found = true;
  break;
      }
  }
  if (found) {
     System.out.println("The array contains the string: " + findString);
  } 
  else {
      System.out.println("The array does not contain the string: " + findString);
   }
 }
}

Next let’s see how to sort a string array.

package com.javacodegeeks.javabasics.stringarray;

public class JavaStringArrayExample {

 public static void main(String args[]) {

  String[] schoolbag = { "Books", "Pens", "Pencils", "Notebooks" }; 

  Arrays.sort(schoolbag);
  for (String element : schoolbag) {
       System.out.println(element);
  }
 }
}

Output:

Books
Notebooks
Pencils
Pens

Now we are going to convert a string array into a string.

package com.javacodegeeks.javabasics.stringarray;

public class JavaStringArrayExample {

 public static void main(String args[]) {

  String[] schoolbag = { "Books", "Pens", "Pencils", "Notebooks" };

  String s = Arrays.toString(schoolbag);
  System.out.println(s);
 }
}

Output:

[Books, Pens, Pencils, Notebooks]

Let’s see how to convert a string array into a set.

package com.javacodegeeks.javabasics.stringarray;

public class JavaStringArrayExample {

 public static void main(String args[]) {

  String[] schoolbag = {"Books", "Pens", "Pens"}; 
  List<string> stringList = Arrays.asList(schoolbag);
  Set<string> stringSet = new HashSet<string>(stringList);
  System.out.println("Size of the list is: " + stringList.size());
  System.out.println("Size of the set is: " + stringSet.size());
 }
}

Output:

Size of the list is: 3
Size of the set is: 2

So now we will see how to convert a list into a string array.

package com.javacodegeeks.javabasics.stringarray;

public class JavaStringArrayExample {

 public static void main(String args[]) {

  List<string> stringList = new ArrayList();
  stringList.add("Books");
  stringList.add("Pens");
  stringList.add("Pencils");
  stringList.add("Notebooks");

  String[] schoolbag = stringList.toArray( new String[] {} );

  for (String element : schoolbag) 
  {
    System.out.println(element);
  }
 }
}

Output:

Books
Pens
Pencils
Notebooks

Finally, let’s see the two-dimensional string array.

package com.javacodegeeks.javabasics.stringarray;

public class JavaStringArrayExample {

 public static void main(String args[]) {
 
  String[][] schoolbagArray = new String[4][2];
  schoolbagArray[0] = new String[] {"Pens", "Pencils"};
  schoolbagArray[1] = new String[] {"Books", "Notebooks"};
  System.out.println( schoolbagArray [1][0] );
 }
}

Output: