SimpleBindings containsKey() method in Java with Examples

The containsKey() method of SimpleBindings class is used to return true if this map which is backing this SimpleBindings object contains a mapping for the specified key. If SimpleBindings object contains this key then the method returns true else false. 

Syntax: 

public boolean containsKey(Object key)

Parameters: This method accepts only one parameters key which is key whose presence in this map is to be tested. 

Return Value: This method returns true if this map contains a mapping for the specified key. 

Exception: This method throws following exceptions:

• NullPointerException: if key is null
• ClassCastException: if key is not String
• IllegalArgumentException: if key is empty String

Java programs to Illustrate the working of containsKey() method: 

Program 1:

Java

// Java program to demonstrate containsKey() method

import javax.script.SimpleBindings;

public class GFG {
    public static void main(String[] args)
    {

        // create simpleBindings object
        SimpleBindings bindings = new SimpleBindings();

        // add some keys with values
        bindings.put("key1", "value1");
        bindings.put("key2", "value2");
        bindings.put("key3", "value3");

        // check key2 is exists in bindings or not
        boolean isKey2Exist = bindings.containsKey("key2");

        // print
        System.out.println("Key2 exists:" + isKey2Exist);
    }
}

Output:

key2 exists:true

Program 2:

Java

// Java program to demonstrate containsKey() method

import javax.script.SimpleBindings;

public class GFG {
    public static void main(String[] args)
    {

        // create simpleBindings object
        SimpleBindings asiaTeamList
            = new SimpleBindings();

        // add team in asiaTeamList
        asiaTeamList.put("team1", "India");
        asiaTeamList.put("team2", "Sri Lanka");
        asiaTeamList.put("team3", "Pakistan");
        asiaTeamList.put("team4", "Bangladesh");

        // check England exists in bindings or not
        boolean isKey2Exist
            = asiaTeamList.containsKey("England");

        // print
        System.out.println("England exists in Asia Team:"
                           + isKey2Exist);
    }
}

Output:

England exists in Asia Team:false

References: https://docs.oracle.com/javase/10/docs/api/javax/script/SimpleBindings.html#containsKey(java.lang.Object)