Java.util.ServiceLoader.toString() Method

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Description

The java.util.ServiceLoader.toString() method returns a string describing this service.

Declaration

Following is the declaration for java.util.ServiceLoader.toString() method

public String toString()

Parameters

NA

Return Value

This method returns a descriptive string

Exception

NA

Example

In order the service to be registered, we need a META-INF/service folder in our classpath. In this particular folder, we need a text file with the name of the interface we implementing containing a single line listing the concrete class name of the implementation. In our case the name of the file is com.tutorialspoint.ServiceProvider and contains this line −

com.tutorialspoint.ServiceImplementation

Our service code is the following −

package com.tutorialspoint;

public class ServiceImplementation extends ServiceProvider {
    
   public String getMessage() {
   return "Hello World";
   }
}

The following code loads the service that is registered and uses it to get the message from the service −

package com.tutorialspoint;

import java.util.ServiceLoader;

public abstract class ServiceProvider {

   public static ServiceProvider getDefault() {

      // load our plugin
      ServiceLoader<ServiceProvider> serviceLoader =
         ServiceLoader.load(ServiceProvider.class);

      // print the serviceLoader as a string
      System.out.println(""+serviceLoader.toString());

      // checking if load was successful
      for (ServiceProvider provider : serviceLoader) {
         return provider;
      }
      throw new Error("Something is wrong with registering the addon");
   }

   public abstract String getMessage();

   public static void main(String[] ignored) {
      
      // create a new provider and call getMessage()
      ServiceProvider provider = ServiceProvider.getDefault();
      System.out.println(provider.getMessage());
   }
}

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

java.util.ServiceLoader[com.tutorialspoint.ServiceProvider]
Hello World