java: can't use constructors in abstract class

Question

I created the following abstract class for job scheduler in red5:

package com.demogames.jobs;

import com.demogames.demofacebook.MysqlDb;
import org.red5.server.api.IClient;
import org.red5.server.api.IConnection;
import org.red5.server.api.IScope;
import org.red5.server.api.scheduling.IScheduledJob;
import org.red5.server.api.so.ISharedObject;
import org.apache.log4j.Logger;
import org.red5.server.api.Red5;

/**
 *
 * @author ufk
 */
abstract public class DemoJob implements IScheduledJob {

protected IConnection conn;
protected IClient client;
protected ISharedObject so;
protected IScope scope;
protected MysqlDb mysqldb;

protected static org.apache.log4j.Logger log = Logger
    .getLogger(DemoJob.class);

protected DemoJob (ISharedObject so, MysqlDb mysqldb){

       this.conn=Red5.getConnectionLocal();
       this.client = conn.getClient();
       this.so=so;
       this.mysqldb=mysqldb;
       this.scope=conn.getScope();
 }

 protected DemoJob(ISharedObject so) {
   this.conn=Red5.getConnectionLocal();
   this.client=this.conn.getClient();
   this.so=so;
   this.scope=conn.getScope();
 }

 protected DemoJob() {
   this.conn=Red5.getConnectionLocal();
   this.client=this.conn.getClient();
   this.scope=conn.getScope();
 }

}

Then i created a simple class that extends the previous one:

public class StartChallengeJob extends DemoJob {

 public void execute(ISchedulingService service) {

   log.error("test");

 }

}

The problem is that my main application can only see the constructor without any parameters. with means i can do new StartChallengeJob() why doesn't the main application sees all the constructors ?

thanks!

Answer 1

Constructors aren't inherited. StartChallengeJob effectively looks like this:

public class StartChallengeJob extends DemoJob {

  public StartChallengeJob() {
    super();
  }

  public void execute(ISchedulingService service) {    
    log.error("test");   
  }    
}

If you want all of the superclass constructor signatures to be available, you'll need to have those constructors in StartChallengeJob too:

public class StartChallengeJob extends DemoJob {

  public DemoJob (ISharedObject so, MysqlDb mysqldb) {
    super(so, mysqldb);
  }

  public DemoJob (ISharedObject so) {
    super(so);
  }

  public StartChallengeJob() {
    super();
  }

  public void execute(ISchedulingService service) {    
    log.error("test");   
  }    
}