Java Properties stringPropertyNames() Method

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Description

The java Properties stringPropertyNames() method returns a set of keys in this property list where the key and its corresponding value are strings, including distinct keys in the default property list if a key of the same name has not already been found from the main properties list. Properties whose key or value is not of type String are omitted.

Declaration

Following is the declaration for java Properties stringPropertyNames() method

public Set<String> stringPropertyNames()

Parameters

NA

Return Value

This method returns a set of keys in this property list where the key and its corresponding value are strings, including the keys in the default property list.

Exception

NA

Getting Names of Keys of Properties as Set of String Example

The following example shows the usage of Java Properties stringPropertyNames() method to print the properties names of a Properties object. We've created a Properties object. Then few entries are added. Using stringPropertyNames() method, all keys are retrieved and printed.

package com.tutorialspoint;

import java.util.Properties;
import java.util.Set;

public class PropertiesDemo {
   public static void main(String[] args) {
      Properties prop = new Properties();

      // add some properties
      prop.put("Height", "200");
      prop.put("Width", "15");

      // save the Property names in the set
      Set<String> set = prop.stringPropertyNames();

      // print the set
      System.out.println("" + set);
   }
}

Output

Let us compile and run the above program, this will produce the following result −

[Width, Height]

Getting Names of Keys of Properties as Set of String After Update Example

The following example shows the usage of Java Properties stringPropertyNames() method to print the properties names of a Properties object. We've created a Properties object. Then few entries are added. Using stringPropertyNames() method, all keys are retrieved and printed.

package com.tutorialspoint;

import java.util.Properties;
import java.util.Set;

public class PropertiesDemo {
   public static void main(String[] args) {
      Properties prop = new Properties();

      // add some properties
      prop.put("Height", "200");
      prop.put("Width", "15");

      // save the Property names in the set
      Set<String> set = prop.stringPropertyNames();

      // add a new property
      prop.put("Length", "150");
	  
      // get the updated set	  
      set = prop.stringPropertyNames();
	  
      // print the set again
      System.out.println("" + set);
   }
}

Output

Let us compile and run the above program, this will produce the following result −

[Length, Height, Width]