java.util.Collections.replaceAll() Method

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Description

The replaceAll(List<T>, T, T) method is used to replace all occurrences of one specified value in a list with another.

Declaration

Following is the declaration for java.util.Collections.replaceAll() method.

public static <T> boolean replaceAll(List<T> list,T oldVal,T newVal)

Parameters

• list − This is the list in which replacement is to occur.

• oldVal − This is the old value to be replaced.

• newVal − This is the new value with which oldVal is to be replaced.

Return Value

The method call returns 'true' if list contained one or more elements e such that (oldVal==null ? e==null : oldVal.equals(e)).

Exception

UnsupportedOperationException − This is thrown if the specified list or its list-iterator does not support the set operation.

Example

The following example shows the usage of java.util.Collections.replaceAll()

package com.tutorialspoint;

import java.util.*;

public class CollectionsDemo {
   public static void main(String[] args) {
      
      // create vector
      Vector<String> vector = new Vector<String>();

      // populate the vector
      vector.add("R");
      vector.add("B");
      vector.add("R");

      System.out.println("Initial values are :"+vector);

      // replace 'R' with 'Replace All'
      Collections.replaceAll(vector, "R", "Replace All");

      System.out.println("Value after replace :"+ vector);
   }
} 

Let us compile and run the above program, this will produce the following result.

Initial values are :[R, B, R]
Value after replace :[Replace All, B, Replace All]