Java ServiceLoader Example
November 17, 2023
ServiceLoader provides the flexibility to load different implementation of a services.
Suppose we have a service class i.e.
CPService as an interface. As we know that there can be more than one implementation of CPService.
Find the
CPService interface.
CPService.java
package com.concretepage.util;
public interface CPService {
public void show();
}
CPService interface.
CPServiceImplOne.java
package com.concretepage.util;
public class CPServiceImplOne implements CPService {
@Override
public void show(){
System.out.println("CPServiceImplOne has been loaded....");
}
}
package com.concretepage.util;
public class CPServiceImplTwo implements CPService {
@Override
public void show(){
System.out.println("CPServiceImplTwo has been loaded....");
}
}
CPServiceImplOne.java. We need to create a folder structure META-INF/services inside our classpath and then create a file with fully qualified Service name. The structure will look like
META-INF
--- services
---- com.util.CPService
META-INF/services/com.util.CPService
com.util.concretepage.CPServiceImplOne
ServiceLoaderDemo.java
package com.concretepage.util;
import java.util.ServiceLoader;
public class ServiceLoaderDemo {
public static void main(String[] args) {
ServiceLoader<CPService> serviceLoader =
ServiceLoader.load(CPService.class);
for (CPService cpService : serviceLoader) {
cpService.show();
}
}
}
CPServiceImplOne has been loaded....
CPServiceImplTwo has been loaded....
