This example shows how to initialize TreeMap with values in Java. .This example also shows How to Initialize TreeMap In Java inline using constructor and Anonymous Subclass .
How to Initialize TreeMap with values in Java?
Now We will discuss several ways for initialize TreeMap with values as following .
1. Initialize TreeMap Using Constructor
We can initialize using constructor We have four type TreeMap Constructor . .
import java.util.HashMap;
import java.util.TreeMap;
public class TreeMapExample {
public static void main(String[] args) {
HashMap<String, String> hashMap = new HashMap<String, String>();
hashMap.put("hcl", "amit");
hashMap.put("tcs","ravi");
hashMap.put("wipro","anmol");
TreeMap<String, String> treeMap = new TreeMap<String,String>(hashMap);
System.out.println("treeMap is ="+ treeMap);
}
}Output :
treeMap is ={hcl=amit, tcs=ravi, wipro=anmol}Anonymous Subclass to Create TreeMap
We can create map with the help of anonymous subclass .
But we should avoid this way to create TreeMap because first we create anonymous class here then TreeMap ,it might me create problem of memory leak.
import java.util.TreeMap;
public class TreeMapExample {
public static void main(String[] args) {
TreeMap<String, String> treeMap = new TreeMap<String, String>() {{
put("hcl", "amit");
put("tcs","ravi");
put("wipro","anmol");
}};
System.out.println("treeMap is ="+ treeMap);
}
}Output :
treeMap is ={hcl=amit, tcs=ravi, wipro=anmol}Use the Double brace initialization to create HashMap with values we should avoid. This example is part of Java TreeMap Example
Reference