﻿ Java: Find greatest key less than or equal to the given key

# Java Collection, TreeMap Exercises: Get the greatest key less than or equal to the given key

## Java Collection, TreeMap Exercises: Exercise-12 with Solution

Write a Java program to get the greatest key less than or equal to the given key.

Sample Solution:-

Java Code:

``````import java.util.*;
import java.util.Map.Entry;
public class Example12 {
public static void main(String args[]) {
// Create a tree map
TreeMap < Integer, String > tree_map1 = new TreeMap < Integer, String > ();
// Put elements to the map
tree_map1.put(10, "Red");
tree_map1.put(20, "Green");
tree_map1.put(40, "Black");
tree_map1.put(50, "White");
tree_map1.put(60, "Pink");

System.out.println("Orginal TreeMap content: " + tree_map1);
System.out.println("Checking the entry for 10: ");
System.out.println("Key is: " + tree_map1.floorKey(10));
System.out.println("Checking the entry for 30: ");
System.out.println("Key is: " + tree_map1.floorKey(30));
System.out.println("Checking the entry for 70: ");
System.out.println("Key is: " + tree_map1.floorKey(70));
}
}
``````

Sample Output:

```Orginal TreeMap content: {10=Red, 20=Green, 40=Black, 50=White, 60=Pink
}
Checking the entry for 10:
Key is: 10
Checking the entry for 30:
Key is: 20
Checking the entry for 70:
Key is: 60```

Java Code Editor:

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## Java: Tips of the Day

getEnumMap

Converts to enum to Map where key is the name and value is Enum itself.

```public static <E extends Enum<E>> Map<String, E> getEnumMap(final Class<E> enumClass) {
return Arrays.stream(enumClass.getEnumConstants())
.collect(Collectors.toMap(Enum::name, Function.identity()));
}
```

Ref: https://bit.ly/3xXcFZt