TreeMap Methods Demo

1. Create Java Project.
2. Create package com.demo
3. Copy and paste the code.

 package com.demo;  
 import java.util.HashMap;  
 import java.util.Map;  
 import java.util.NavigableMap;  
 import java.util.SortedMap;  
 import java.util.TreeMap;  
 import java.util.Map.Entry;  
 import com.demo.model.Employee;  
 public class TreeMapMethodsDemo {  
      public static void main(String[] args) {  
           Map<String, String> treeMap = new TreeMap<String, String>();  
           treeMap.put("a", "aa");  
           treeMap.put("c", "cc");  
           treeMap.put("e", "ee");  
           treeMap.put("b", "bb");  
           System.out.println("--** printing the elements : constructor 1 **--");  
           for(Entry<String, String> entry : treeMap.entrySet()){  
                System.out.println("key = "+entry.getKey()+" val = "+entry.getValue());  
           }  
           System.out.println("--** printing the elements : constructor 2 **--");  
           System.out.println("-- TreeMap with same salary having comparator --");  
           Map<Employee,Object> treeMap2 = new TreeMap<Employee,Object>(Employee.SalaryComparator);  
           treeMap2.put(new Employee("Ritu", 26, 10000), "Manager");  
           treeMap2.put(new Employee("Nupur", 28, 4000), "Assistant");  
           treeMap2.put(new Employee("Nagma", 40, 4000), "MD");  
           for(Entry<Employee, Object> entry : treeMap2.entrySet()){  
                System.out.println("key = "+entry.getKey()+" val = "+entry.getValue());  
           }  
           System.out.println("-- TreeMap with diff salary having comparator --");  
           Map<Employee,Object> treeMap3 = new TreeMap<Employee,Object>(Employee.SalaryComparator);  
           treeMap3.put(new Employee("Ritu", 35, 12000), "Manager");  
           treeMap3.put(new Employee("Nupur", 56, 13000), "Assistant");  
           treeMap3.put(new Employee("Nagma", 24, 15000), "MD");  
           for(Entry<Employee, Object> entry3 : treeMap3.entrySet()){  
                System.out.println("key = "+entry3.getKey()+" val = "+entry3.getValue());  
           }  
           System.out.println("--** printing the elements : constructor 3 **--");  
           Map<String,String> map1 = new HashMap<String, String>();  
           map1.put("a", "A");  
           map1.put("b", "B");  
           Map<String,String> treeMap4 = new TreeMap<>(map1);  
           for(Entry<String, String> entry : treeMap4.entrySet()){  
                System.out.println("key = "+entry.getKey()+" val = "+entry.getValue());  
           }  
           System.out.println("-- printing TreeMap values --");  
           TreeMap<Integer, String> teeMap = new TreeMap<Integer, String>();  
           teeMap.put(1, "AA");  
           teeMap.put(2, "BB");  
           teeMap.put(3, "CC");  
           teeMap.put(4, "DD");  
           teeMap.put(6, "GG");  
           teeMap.put(7, "UU");  
           teeMap.put(9, "FF");  
           teeMap.put(12, "OO");  
           for(Entry<Integer, String> entry : teeMap.entrySet()){  
                System.out.println("key = "+entry.getKey()+" val = "+entry.getValue());  
           }  
           System.out.println("--printing first key => "+teeMap.firstKey());  
           System.out.println("--printing last key => "+teeMap.lastKey());  
           System.out.println("--poll first entry => "+teeMap.pollFirstEntry());  
           System.out.println("--poll last entry => "+teeMap.pollLastEntry());  
           System.out.println("--lower key => "+teeMap.lowerKey(3));  
           System.out.println("--lower entry => "+teeMap.lowerEntry(4));  
           System.out.println("--floor key => "+teeMap.floorKey(2));  
           System.out.println("--floor entry => "+teeMap.floorEntry(4));  
           System.out.println("-- ceilingKey => "+teeMap.ceilingKey(5));  
           System.out.println("-- ceilingEntry => "+teeMap.ceilingEntry(4));  
           System.out.println("-- Print the desending treeMap --");  
           NavigableMap<Integer, String> desTreeMap = teeMap.descendingMap();  
           for(Entry<Integer, String> entry : desTreeMap.entrySet()){  
                System.out.println("key = "+entry.getKey()+" val = "+entry.getValue());  
           }  
           System.out.println("-- Print the sorted HeadMap --");  
           SortedMap<Integer, String> sortedHeadMap = teeMap.headMap(6);  
           for(Entry<Integer, String> entry : sortedHeadMap.entrySet()){  
                System.out.println("key = "+entry.getKey()+" val = "+entry.getValue());  
           }  
           System.out.println("-- Print the sorted TailMap --");  
           SortedMap<Integer, String> sortedTailMap = teeMap.tailMap(6);  
           for(Entry<Integer, String> entry : sortedTailMap.entrySet()){  
                System.out.println("key = "+entry.getKey()+" val = "+entry.getValue());  
           }  
           System.out.println("-- Print the sorted submap --");  
           SortedMap<Integer, String> sortedSubMap = teeMap.subMap(2, 7);  
           for(Entry<Integer, String> entry : sortedSubMap.entrySet()){  
                System.out.println("key = "+entry.getKey()+" val = "+entry.getValue());  
           }  
      }  
 }  

OUTPUT 

--** printing the elements : constructor 1 **--
key = a val = aa
key = b val = bb
key = c val = cc
key = e val = ee
--** printing the elements : constructor 2 **--
-- TreeMap with same salary having comparator --
key = Employee [name=Nupur, age=28, salary=4000.0] val = MD
key = Employee [name=Ritu, age=26, salary=10000.0] val = Manager
-- TreeMap with diff salary having comparator --
key = Employee [name=Ritu, age=35, salary=12000.0] val = Manager
key = Employee [name=Nupur, age=56, salary=13000.0] val = Assistant
key = Employee [name=Nagma, age=24, salary=15000.0] val = MD
--** printing the elements : constructor 3 **--
key = a val = A
key = b val = B
-- printing TreeMap values --
key = 1 val = AA
key = 2 val = BB
key = 3 val = CC
key = 4 val = DD
key = 6 val = GG
key = 7 val = UU
key = 9 val = FF
key = 12 val = OO
--printing first key => 1
--printing last key => 12
--poll first entry => 1=AA
--poll last entry => 12=OO
--lower key => 2
--lower entry => 3=CC
--floor key => 2
--floor entry => 4=DD
-- ceilingKey => 6
-- ceilingEntry => 4=DD
-- Print the desending treeMap --
key = 9 val = FF
key = 7 val = UU
key = 6 val = GG
key = 4 val = DD
key = 3 val = CC
key = 2 val = BB
-- Print the sorted HeadMap --
key = 2 val = BB
key = 3 val = CC
key = 4 val = DD
-- Print the sorted TailMap --
key = 6 val = GG
key = 7 val = UU
key = 9 val = FF
-- Print the sorted submap --
key = 2 val = BB
key = 3 val = CC
key = 4 val = DD
key = 6 val = GG