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Java Collection, TreeMap Exercises: Remove and get a key-value mapping associated with the greatest key in this map

Java Collection, TreeMap Exercises: Exercise-20 with Solution

Write a Java program to remove and get a key-value mapping associated with the greatest key in this map.

Sample Solution:-

Java Code:

import java.util.*;
import java.util.Map.Entry;  
public class Example20 {  
          public static void main(String args[]) {

  // Create a tree map
  TreeMap < Integer, String > tree_map = new TreeMap < Integer, String > ();

  // Put elements to the map 
  tree_map.put(10, "Red");
  tree_map.put(20, "Green");
  tree_map.put(40, "Black");
  tree_map.put(50, "White");
  tree_map.put(60, "Pink");

  // polling first entry
  System.out.println("Value before poll: " + tree_map);
  System.out.println("Value returned: " + tree_map.pollLastEntry());
  System.out.println("Value after poll: " + tree_map);
 }
}

Sample Output:

Value before poll: {10=Red, 20=Green, 40=Black, 50=White, 60=Pink}     
Value returned: 60=Pink                                                
Value after poll: {10=Red, 20=Green, 40=Black, 50=White} 

Java Code Editor:

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Java: Tips of the Day

Try and catch:

Java is excellent at catching errors, but it can only recover gracefully if you tell it what to do. The cascading hierarchy of attempting to perform an action in Java starts with try, falls back to catch, and ends with finally. Should the try clause fail, then catch is invoked, and in the end, there's always finally to perform some sensible action regardless of the results. Here's an example:

try {
        cmd = parser.parse(opt, args); 
       
        if(cmd.hasOption("help")) {
                HelpFormatter helper = new HelpFormatter();
                helper.printHelp("Hello ", opt);
                System.exit(0);
                }
        else {
                if(cmd.hasOption("shell") || cmd.hasOption("s")) {
                String target = cmd.getOptionValue("tgt");
                } // else
        } // fi
} catch (ParseException err) {
        System.out.println(err);
        System.exit(1);
        } //catch
        finally {
                new Hello().helloWorld(opt);
        } //finally
} //try

It's a robust system that attempts to avoid irrecoverable errors or, at least, to provide you with the option to give useful feedback to the user. Use it often, and your users will thank you!

Ref: https://red.ht/3EZc9OC