Java System setProperties() Method

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Description

The Java System setProperties() method sets the system properties to the Properties argument.

Declaration

Following is the declaration for java.lang.System.setProperties() method

public static void setProperties(Properties props)

Parameters

props − This is the new system properties.

Return Value

This method does not return any value.

Exception

SecurityException − if a security manager exists and its checkPropertiesAccess method doesn't allow access to the system properties.

Example: Clearing User Directory and Setting New Path

The following example shows the usage of Java System setProperties() method. In this example, we've cleared the current user.dir system property using System.clearProperty() method. We've used the returned value of clearProperty() to print the previous user.dir property value. Using setProperties() method, a new path is set as user.dir via properties object and using getProperty(), this updated property is retrieved and printed.

package com.tutorialspoint;

public class SystemDemo {

   public static void main(String[] args) {

      // returns the previous string value of the system property
      String userDir = System.clearProperty("user.dir");
      System.out.println("Previous user.dir = " + userDir);

      // sets the new property	  
      Properties p = System.getProperties();
      p.put("user.dir", "C:/tutorialspoint/java");
      System.setProperties(p);

      // gets the system property after changes done by setProperty
      System.out.println("Current user.dir = " + System.getProperty("user.dir"));
   }
} 

Output

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

Previous user.dir = C:\Users\Tutorialspoint\eclipse-workspace\Tutorialspoint
Current user.dir = C:/tutorialspoint/java

Example: Clearing Java Class Path and Setting New Path

The following example shows the usage of Java System setProperties() method. In this example, we've cleared the current java.class.path system property using System.clearProperty() method. We've used the returned value of clearProperty() to print the previous java.class.path property value. Using setProperties() method, a new path is set as java.class.path via properties object and using getProperty(), this updated property is retrieved and printed.

package com.tutorialspoint;

public class SystemDemo {

   public static void main(String[] args) {

      // returns the previous string value of the system property
      String classPath = System.clearProperty("java.class.path");
      System.out.println("Previous Class Path = " + classPath);

      // sets the new property	  
      Properties p = System.getProperties();
      p.put("java.class.path", "C:/tutorialspoint/java");
      System.setProperties(p);

      // gets the system property after changes done by setProperty
      System.out.println("Current Class Path = " + System.getProperty("java.class.path"));
   }
} 

Output

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

Previous Class Path = C:\Users\Tutorialspoint\eclipse-workspace\Tutorialspoint\bin;C:\Users\Tutorialspoint\eclipse-workspace\Tutorialspoint\lib\jmh-core-1.37.jar;C:\Users\Tutorialspoint\eclipse-workspace\Tutorialspoint\lib\jmh-generator-annprocess-1.37.jar;C:\Users\Tutorialspoint\eclipse-workspace\Tutorialspoint\lib
Current Class Path = C:/tutorialspoint/java

Example: Clearing Non-Existing Property and Setting New Value

The following example shows the usage of Java System setProperties() method. In this example, we've cleared the current tmp.dir system property using System.clearProperty() method. We've used the returned value of clearProperty() to print the previous tmp.dir property value as null. Using setProperties() method, a new path is set as tmp.dir via properties object and using getProperty(), this updated property is retrieved and printed.

package com.tutorialspoint;

public class SystemDemo {

   public static void main(String[] args) {

      // returns the previous string value of the system property
      String tmpDir = System.clearProperty("tmp.dir");
      System.out.println("Previous Temporary Dir = " + tmpDir);
	  
      // sets the new property	  
      Properties p = System.getProperties();
      p.put("tmp.dir", "C:/tutorialspoint/java");
      System.setProperties(p);

      // gets the system property after changes done by setProperty
      System.out.println("Current Temporary Dir = " + System.getProperty("tmp.dir"));
   }
}  

Output

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

Previous Temporary Dir = null
Current Temporary Dir = C:/tutorialspoint/java