{"id":79062,"date":"2020-06-13T09:00:34","date_gmt":"2020-06-13T03:30:34","guid":{"rendered":"https:\/\/techvidvan.com\/tutorials\/?p=79062"},"modified":"2020-06-13T09:00:34","modified_gmt":"2020-06-13T03:30:34","slug":"merge-two-arrays-in-java","status":"publish","type":"post","link":"https:\/\/techvidvan.com\/tutorials\/merge-two-arrays-in-java\/","title":{"rendered":"How to Merge Two Arrays in Java"},"content":{"rendered":"

We hope you are enjoying reading our Java articles and are learning Java in an interesting way. In this article, we have come with a new tutorial that will teach you about merging two arrays in Java.<\/p>\n

We must say that you are all now very familiar and comfortable with arrays in Java as we covered the concept of arrays in many articles.<\/p>\n

In this article, we will learn how we can merge two different arrays in Java and form a resulting array without changing the sequence of its elements.<\/p>\n

\"Merge<\/a><\/p>\n

Merge two Arrays in Java<\/h3>\n

We know that an array is a contiguous memory location of elements that are of the same datatype. We can perform several operations on a single array but merging two arrays involves two different arrays.<\/p>\n

Merging means concatenating elements of two arrays into a single array. The elements of the first array precede the elements of the second array.<\/p>\n

For example:<\/strong><\/p>\n

Suppose there are three arrays named array1, array2 and array3<\/strong>. We will merge array1 and array2 into array3 as follows:<\/p>\n

int array1[ ] = { 1, 2, 3, 4, 5 };\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \/\/ first array<\/strong>
\nint array2[ ] = { 6, 7, 8, 9, 10 };\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0\/\/second array<\/strong>
\nint array3[ ] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \/\/third array(resultant array)<\/strong><\/p>\n

We can do this by manual method of combining two arrays or we can also use some predefined methods and libraries to accomplish this task. There are many ways to merge two arrays in Java.<\/p>\n

Let\u2019s discuss each of them with implementation.<\/p>\n

Different Ways to Merge Arrays in Java<\/h3>\n

\"Different<\/a><\/p>\n

Following are some different ways that we can use to merge two arrays in Java:<\/p>\n

1. Using Conventional\/manual<\/strong> method
\n2. Using arraycopy()<\/strong> method of Java
\n3. Using Java Collections<\/strong>
\n4. Using Java Stream API<\/strong>
\n5. Using ObjectArrays<\/strong> class of Guava library<\/p>\n

1. Manual Method in Java<\/h4>\n

In this method, we do not use any predefined method for merging two arrays. We just take one array and then the second array. Then, we calculate the lengths of both the arrays and add the lengths.<\/p>\n

We create a new array with the length as the sum of lengths of these two arrays. Now we just start adding the elements of each array in the resulting array. As a result of this method, we get a resulting array as the concatenation of two arrays.<\/p>\n

Let\u2019s see the code to understand this method:<\/p>\n

Code to understand the manual method of merging two arrays in Java:<\/strong><\/p>\n

package com.techvidvan.mergearrays;\nimport java.util.Arrays;\npublic class ManualMethod {\n  public static void main(String[] args) {\n    \/\/declaring two character arrays\n    int[] array1 = {\n      1,\n      2,\n      3,\n      4\n    };\n    int[] array2 = {\n      5,\n      6,\n      7,\n      8\n    };\n\n    \/\/Calculating sum of length of two arrays\n    int length = array1.length + array2.length;\n\n    System.out.println(\"First Array is: \");\n    for (int i = 0; i < array1.length; i++) {\n      System.out.print(\" \" + array1[i]);\n    }\n    System.out.println(\" \");\n\n    System.out.println(\"Second Array is: \");\n    for (int i = 0; i < array2.length; i++) {\n      System.out.print(\" \" + array2[i]);\n    }\n\n    \/\/Creating a resulting array of the calculated length\n    int[] result = new int[length];\n    int position = 0;\n\n    \/\/for each loop to add array1 elements to the resulting array\n    for (int element: array1) {\n      result[position] = element;\n      position++;\n    }\n\n    \/\/for each loop to add array2 elements to the resulting array\n    for (int element: array2) {\n      result[position] = element;\n      position++;\n    }\n\n    System.out.println(\"\\nThe resulting array after merging two arrays is: \");\n    System.out.println(Arrays.toString(result));\n  }\n}<\/pre>\n
Output<\/strong><\/p>\n
First Array is:
\n1 2 3 4
\nSecond Array is:
\n5 6 7 8
\nThe resulting array after merging two arrays is:
\n[1, 2, 3, 4, 5, 6, 7, 8]<\/div>\n
2. arraycopy() Method in Java<\/h4>\n
Java arraycopy() is the method of the System class which belongs to the java.lang package. It copies an array from the specified source array to the specified position of the destination array.<\/p>\n
The number of elements copied is equal to the length argument.<\/p>\n
Syntax:<\/strong><\/p>\n
public static void arraycopy(Object source, int source_position, Object destination, int destination_position, int length)<\/strong><\/p>\n
Parameters of arraycopy() method:<\/strong><\/p>\n