[JAVA] Errore "Cannot find symbol" in fase di compilazione

[marziomorandi]

Ho le due classi seguenti

Classe SWA

package com.prova;

public abstract class SWA extends Exception
{
	protected Throwable	core = null;
	public final static int INFORMATION = 1;
	public final static int WARNING = 2;
	public final static int CRITICAL = 3;
	public final static int FATAL = 4;
	private int		severity = INFORMATION;
	public SWA(int severity, String message)
	{
		super(message);

		this.severity = severity;
	}
	public SWA(Throwable core, int severity, String message)
	{
		this(severity, message);

		this.core = core;
	}
	public void setCoreException(Throwable e)
	{
		this.core = core;
	}
	public Throwable getCoreException()
	{
		return core;
	}
	public final void setSeverity(int severity)
	{
		this.severity = severity;
	}
	public final int getSeverity()
	{
		return severity;
	}

}

Classe SWB

package com.prova;

public class SWB extends SWA
{
	public SWB(Throwable core, int severity, String message)
	{
		super(core, severity, message);
	}
	public SWB(int severity, String message)
	{
		super(severity, message);
	}

}

Quando tento di compilare SWB mi ritorna l'errore

cannot find symbol
symbol: class SWA

Qualcuno mi può aiutare?

Grazie Marzio