How to Merge Two Arrays In Java?

To merge two arrays in Java, you can use the System.arraycopy() method or the Arrays.copyOf() method.

1. Using System.arraycopy(): Create a new array with the combined length of the two arrays. Use the System.arraycopy() method to copy the elements of each array into the new array.
2. Using Arrays.copyOf(): Create a new array with the combined length of the two arrays. Use the Arrays.copyOf() method to copy the elements of each array into the new array.

Both methods will allow you to merge two arrays into a single array in Java.

How to merge two arrays in Java using ArrayList?

To merge two arrays in Java using ArrayList, you can follow these steps:

1. Create two arrays that you want to merge.
2. Create two ArrayList objects and add the elements of the arrays to the ArrayList objects.
3. Use the addAll() method of ArrayList to add all the elements of the second ArrayList to the first ArrayList.
4. Finally, convert the merged ArrayList back to an array using the toArray() method.

Here is an example code snippet to demonstrate how to merge two arrays in Java using ArrayList:

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import java.util.ArrayList;
import java.util.Arrays;

public class MergeArrays {
    
    public static void main(String[] args) {
        // Create two arrays to merge
        Integer[] array1 = {1, 2, 3};
        Integer[] array2 = {4, 5, 6};
        
        // Create ArrayList objects and add elements of the arrays
        ArrayList<Integer> list1 = new ArrayList<>(Arrays.asList(array1));
        ArrayList<Integer> list2 = new ArrayList<>(Arrays.asList(array2));
        
        // Merge the two ArrayList objects
        list1.addAll(list2);
        
        // Convert the merged ArrayList back to an array
        Integer[] mergedArray = list1.toArray(new Integer[0]);
        
        // Print the merged array
        System.out.println(Arrays.toString(mergedArray));
    }
}

When you run this code, you will see the merged array printed as [1, 2, 3, 4, 5, 6].

How to merge two arrays of strings in Java?

There are multiple ways to merge two arrays of strings in Java. One simple way is to use the Stream class to combine the arrays and then collect them into a single array.

Here is an example of how you can do this:

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import java.util.Arrays;
import java.util.stream.Stream;

public class MergeArrays {
    public static void main(String[] args) {
        String[] array1 = {"Hello", "World"};
        String[] array2 = {"Java", "Programming"};

        // Merge two arrays using Streams
        String[] mergedArray = Stream.concat(Arrays.stream(array1), Arrays.stream(array2))
                .toArray(String[]::new);

        // Print the merged array
        for (String s : mergedArray) {
            System.out.print(s + " ");
        }
    }
}

In this example, we first import the necessary classes and create two arrays of strings (array1 and array2). We then use the Stream.concat method to merge the two arrays into a single stream and then collect them into a new array using the toArray method. Finally, we loop through the merged array and print out the strings.

How to merge two unsorted arrays in Java?

One way to merge two unsorted arrays in Java is to create a new array with the combined length of both arrays, and then iterate through each element of both arrays, adding them to the new array.

Here is an example code snippet that demonstrates this:

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public class MergeArrays {
    
    public static void main(String[] args) {
        
        int[] array1 = {3, 6, 2, 8, 1};
        int[] array2 = {5, 4, 9, 7};
        
        int[] mergedArray = mergeArrays(array1, array2);
        
        for (int num : mergedArray) {
            System.out.print(num + " ");
        }
    }
    
    public static int[] mergeArrays(int[] arr1, int[] arr2) {
        
        int len1 = arr1.length;
        int len2 = arr2.length;
        
        int[] mergedArray = new int[len1 + len2];
        
        int i = 0;
        for (int num : arr1) {
            mergedArray[i] = num;
            i++;
        }
        
        for (int num : arr2) {
            mergedArray[i] = num;
            i++;
        }
        
        return mergedArray;
    }
}

In this code, the mergeArrays method takes two arrays as input and returns a new array that contains all elements from both input arrays. The main method creates two unsorted arrays, calls the mergeArrays method, and prints the merged array.

How to merge two arrays of different sizes in Java?

One way to merge two arrays of different sizes in Java is to create a new array of the combined size, then copy the elements from the two arrays into the new array.

Here is an example of how you can do this:

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public static void main(String[] args) {
    int[] array1 = {1, 2, 3, 4};
    int[] array2 = {5, 6, 7};

    int[] mergedArray = new int[array1.length + array2.length];

    System.arraycopy(array1, 0, mergedArray, 0, array1.length);
    System.arraycopy(array2, 0, mergedArray, array1.length, array2.length);

    for (int i = 0; i < mergedArray.length; i++) {
        System.out.print(mergedArray[i] + " ");
    }
}

In this example, we first create a new array called mergedArray with a size equal to the sum of the lengths of array1 and array2. We then use System.arraycopy() to copy the elements of array1 and array2 into mergedArray. Finally, we loop through mergedArray and print out each element.

This will result in the printed output: 1 2 3 4 5 6 7.