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how to copy map content to another treemap?


TreeMap

TreeMap extends AbstractMap class and implements the NavigableMap interface. It contains the elements in key-value pair form. It maintains ascending order for its elements. It not allowed duplicate key.

Note: A TreeMap can have only one null key but can have multiple null values.

We can use putAll() method to copy map content to another treemap.

putAll(Map m): Puts all the entries from m into this map.
Syntax: public void putAll(Map m)

Example

package com.codesjava;
 
import java.util.TreeMap;
 
public class Test {
  public static void main(String args[]){
	//Create TreeMap object.
	TreeMap<Integer, String> treeMap = new TreeMap<Integer, String>();
 
	//Add objects to the TreeMap.
	treeMap.put(4, "Roxy");
	treeMap.put(2, "Sunil");
	treeMap.put(5, "Sandy");
	treeMap.put(1, "Munish");
	treeMap.put(3, "Pardeep");
 
	//Print the TreeMap object.
	System.out.println("TreeMap elements:");
 
        System.out.println(treeMap);
 
	//Create sub map		
        TreeMap<Integer, String> subMap = new TreeMap<Integer, String>();
        subMap.put(6, "Sachin");
        subMap.put(7, "Sahil");
        //Copy submap elements into treemap
        treeMap.putAll(subMap); 
        //Print the TreeMap object.
      	System.out.println("TreeMap elements:");
      	System.out.println(treeMap);
  }
}

Output

TreeMap elements:
{1=Munish, 2=Sunil, 3=Pardeep, 4=Roxy, 5=Sandy}
TreeMap elements:
{1=Munish, 2=Sunil, 3=Pardeep, 4=Roxy, 5=Sandy, 6=Sachin, 7=Sahil}


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