MySQL - Syntax error en sentencia java

public void enviarMensaje(String emisor, String receptor, String asunto, String mensaje) {

	try {

		String consulta="insert into mensajes ('emisor','receptor','asunto','mensaje')" + "values(?,?,?,?)";

		PreparedStatement pstm=cn.getConnection().prepareStatement(consulta);

		pstm.setString(1, emisor);

		pstm.setString(2, receptor);

		pstm.setString(3, asunto);

		pstm.setString(4, mensaje);

		pstm.execute();

		cn.getConnection().close();

	} catch (SQLException e) {

		// TODO Auto-generated catch block

		e.printStackTrace();

	}

}

java.sql.SQLException: Syntax error or access violation message from server: "You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ''emisor','receptor','asunto','mensaje')values('lucasciffoni@navalmail.com','luca' at line 1"

	at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2001)

	at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1168)

	at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1279)

	at com.mysql.jdbc.Connection.execSQL(Connection.java:2281)

	at com.mysql.jdbc.PreparedStatement.execute(PreparedStatement.java:1419)

	at Bdd.BDDUser.enviarMensaje(BDDUser.java:88)

	at Plataforma.BandejaDeEntrada$2$1.actionPerformed(BandejaDeEntrada.java:86)

	at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)

	at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)

	at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)

	at javax.swing.DefaultButtonModel.setPressed(Unknown Source)

	at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)

	at java.awt.Component.processMouseEvent(Unknown Source)

	at javax.swing.JComponent.processMouseEvent(Unknown Source)

	at java.awt.Component.processEvent(Unknown Source)

	at java.awt.Container.processEvent(Unknown Source)

	at java.awt.Component.dispatchEventImpl(Unknown Source)

	at java.awt.Container.dispatchEventImpl(Unknown Source)

	at java.awt.Component.dispatchEvent(Unknown Source)

	at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)

	at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)

	at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)

	at java.awt.Container.dispatchEventImpl(Unknown Source)

	at java.awt.Window.dispatchEventImpl(Unknown Source)

	at java.awt.Component.dispatchEvent(Unknown Source)

	at java.awt.EventQueue.dispatchEventImpl(Unknown Source)

	at java.awt.EventQueue.access$500(Unknown Source)

	at java.awt.EventQueue$3.run(Unknown Source)

	at java.awt.EventQueue$3.run(Unknown Source)

	at java.security.AccessController.doPrivileged(Native Method)

	at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)

	at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)

	at java.awt.EventQueue$4.run(Unknown Source)

	at java.awt.EventQueue$4.run(Unknown Source)

	at java.security.AccessController.doPrivileged(Native Method)

	at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)

	at java.awt.EventQueue.dispatchEvent(Unknown Source)

	at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)

	at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)

	at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)

	at java.awt.EventDispatchThread.pumpEvents(Unknown Source)

	at java.awt.EventDispatchThread.pumpEvents(Unknown Source)

	at java.awt.EventDispatchThread.run(Unknown Source)

String consulta="insert into mensajes (emisor,receptor,asunto,mensaje)" + "values(?,?,?,?)";