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Java Collections - Arrays.copyOf() Examples

Java Collections Java Java API 

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Class:

java.util.Arrays

java.lang.Objectjava.lang.Objectjava.util.Arraysjava.util.ArraysLogicBig

Methods:

These methods copy the specified array, truncating or padding with default values (if necessary) so the copy has the specified length. 

public static <T> T[] copyOf(T[] original,
                             int newLength)

public static <T,U> T[] copyOf(U[] original,
                               int newLength,
                               Class<? extends T[]> newType)

public static byte[] copyOf(byte[] original,
                            int newLength)

public static short[] copyOf(short[] original,
                             int newLength)

public static int[] copyOf(int[] original,
                           int newLength)

public static long[] copyOf(long[] original,
                            int newLength)

public static char[] copyOf(char[] original,
                            int newLength)

public static float[] copyOf(float[] original,
                             int newLength)

public static double[] copyOf(double[] original,
                              int newLength)

public static boolean[] copyOf(boolean[] original,
                               int newLength)

Examples


package com.logicbig.example.arrays;

import java.util.Arrays;

public class CopyOfExample {

    public static void main(String... args) {
        boolean[] arr = {false, true, true};
        boolean[] newArr = Arrays.copyOf(arr, 5);
        System.out.println(Arrays.toString(newArr));
    }
}

Output

[false, true, true, false, false]




package com.logicbig.example.arrays;

import java.util.Arrays;

public class CopyOfExample2 {

    public static void main(String... args) {
        int[] arr = Arrays.copyOf(new int[]{3, 5}, 6);
        System.out.println(Arrays.toString(arr));
    }
}

Output

[3, 5, 0, 0, 0, 0]




package com.logicbig.example.arrays;

import java.util.Arrays;

public class CopyOfExample3 {

    public static void main(String... args) {
        char[] arr = Arrays.copyOf(new char[]{'a', 'c'}, 4);
        System.out.println(Arrays.toString(arr));
    }
}

Output

[a, c,  ,  ]




package com.logicbig.example.arrays;

import java.util.Arrays;

public class CopyOfExample4 {

    public static void main(String... args) {
        double[] arr = Arrays.copyOf(new double[]{1.3, 2.5}, 4);
        System.out.println(Arrays.toString(arr));
    }
}

Output

[1.3, 2.5, 0.0, 0.0]

package com.logicbig.example.arrays;

import java.util.Arrays;

public class CopyOfExample5 {

    public static void main(String... args) {
        String[] arr = Arrays.copyOf(new String[]{"apple", "pie"}, 5);
        System.out.println(Arrays.toString(arr));
    }
}

Output

[apple, pie, null, null, null]




package com.logicbig.example.arrays;

import java.math.BigInteger;
import java.util.Arrays;

public class CopyOfExample6 {

    public static void main(String... args) {
        BigInteger[] arr = Arrays.copyOf(
                new BigInteger[]{BigInteger.TEN, BigInteger.ONE}, 4
        );
        System.out.println(Arrays.toString(arr));

    }
}

Output

[10, 1, null, null]




package com.logicbig.example.arrays;

import java.util.Arrays;

public class CopyOfExample7 {

    public static void main(String... args) {

        Number[] arr = Arrays.copyOf(new Integer[]{1, 4}, 5, Number[].class);
        System.out.println(Arrays.toString(arr));
    }
}

Output

[1, 4, null, null, null]

package com.logicbig.example.arrays;

import java.util.Arrays;

public class CopyOfExample8 {

    public static void main(String... args) {
        A[] arr = Arrays.copyOf(new B[]{new B(), new B()}, 5, A[].class);
        System.out.println(Arrays.toString(arr));
    }

    private static class A {
    }

    private static class B extends A{
    }

}

Output

[com.logicbig.example.arrays.CopyOfExample8$B@64775c35, com.logicbig.example.arrays.CopyOfExample8$B@22d47061, null, null, null]

See Also