TreeMap lowerEntry() method in Java with Examples
The lowerEntry() method of java.util.TreeMap class is used to return a key-value mapping associated with the greatest key strictly less than the given key, or null if there is no such key
Syntax:
public Map.Entry lowerEntry(K key)
Parameters: This method takes the key as a parameter for which the lower entry is to be found.
Return Value: This method returns an entry with the greatest key less than key, or null if there is no such key.
Exception: This method throws NullPointerException if the specified key is null and this map uses natural ordering, or its comparator does not permit null keys.
Below are the examples to illustrate the lowerEntry() method
Example 1:
Java
import java.util.*;
public class GFG1 {
public static void main(String[] argv)
throws Exception
{
try {
TreeMap<Integer, String>
treemap = new TreeMap<Integer, String>();
treemap.put( 1 , "One" );
treemap.put( 2 , "Two" );
treemap.put( 3 , "Three" );
treemap.put( 4 , "Four" );
treemap.put( 5 , "Five" );
System.out.println( "TreeMap: " + treemap);
Map.Entry<Integer, String>
value
= treemap.lowerEntry( 3 );
System.out.println( "The lowerEntry value "
+ " for 3: " + value);
}
catch (NullPointerException e) {
System.out.println( "Exception thrown : " + e);
}
}
}
|
Output:
TreeMap: {1=One, 2=Two, 3=Three, 4=Four, 5=Five}
The lowerEntry value for 3: 2=Two
Example 2: For NullPointerException
Java
import java.util.*;
public class GFG1 {
public static void main(String[] argv)
throws Exception
{
try {
TreeMap<Integer, String>
treemap = new TreeMap<Integer, String>();
treemap.put( 1 , "One" );
treemap.put( 2 , "Two" );
treemap.put( 3 , "Three" );
treemap.put( 4 , "Four" );
treemap.put( 5 , "Five" );
System.out.println( "TreeMap: " + treemap);
System.out.println( "Trying to get"
+ " the lowerEntry value"
+ " for value NULL" );
Map.Entry<Integer, String>
value
= treemap.lowerEntry( null );
System.out.println( "Value is: " + value);
}
catch (NullPointerException e) {
System.out.println( "Exception thrown : " + e);
}
}
}
|
Output:
TreeMap: {1=One, 2=Two, 3=Three, 4=Four, 5=Five}
Trying to get the lowerEntry value for value NULL
Exception thrown : java.lang.NullPointerException
Last Updated :
08 Jun, 2021
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