1. If I enter the following string in the Remote Process input line:

service:jmx:rmi:///jndi/rmi://foo:bar

No error message is reported. The Connection dialog just disappears.

At the same time, the following is printed to the terminal:

Exception in thread "JConsole.addUrl" java.lang.NumberFormatException: For input string: "bar"
        at java.lang.NumberFormatException.forInputString(NumberFormatException.java:48)
        at java.lang.Integer.parseInt(Integer.java:447)
        at java.lang.Integer.parseInt(Integer.java:497)
        at com.sun.jndi.url.rmi.rmiURLContext.getRootURLContext(rmiURLContext.java:86)
        at com.sun.jndi.toolkit.url.GenericURLContext.lookup(GenericURLContext.java:182)
        at javax.naming.InitialContext.lookup(InitialContext.java:351)
        at javax.management.remote.rmi.RMIConnector.findRMIServerJNDI(RMIConnector.java:1871)
        at javax.management.remote.rmi.RMIConnector.findRMIServer(RMIConnector.java:1841)
        at javax.management.remote.rmi.RMIConnector.connect(RMIConnector.java:255)
        at javax.management.remote.JMXConnectorFactory.connect(JMXConnectorFactory.java:248)
        at sun.tools.jconsole.ProxyClient.connect(ProxyClient.java:116)
        at sun.tools.jconsole.ProxyClient.<init>(ProxyClient.java:87)
        at sun.tools.jconsole.ProxyClient.getProxyClient(ProxyClient.java:173)
        at sun.tools.jconsole.JConsole$2.run(JConsole.java:404)

2. The same if I enter '99999' as a port number, but a different exception:

Exception in thread "JConsole.addUrl" java.lang.ClassCastException: com.sun.jndi.rmi.registry.RegistryContext cannot be cast to javax.management.remote.rmi.RMIServer
        at javax.management.remote.rmi.RMIConnector.narrowJRMPServer(RMIConnector.java:1882)
        at javax.management.remote.rmi.RMIConnector.findRMIServerJNDI(RMIConnector.java:1877)
        at javax.management.remote.rmi.RMIConnector.findRMIServer(RMIConnector.java:1841)
        at javax.management.remote.rmi.RMIConnector.connect(RMIConnector.java:255)
        at javax.management.remote.JMXConnectorFactory.connect(JMXConnectorFactory.java:248)
        at sun.tools.jconsole.ProxyClient.connect(ProxyClient.java:116)
        at sun.tools.jconsole.ProxyClient.<init>(ProxyClient.java:87)
        at sun.tools.jconsole.ProxyClient.getProxyClient(ProxyClient.java:173)
        at sun.tools.jconsole.JConsole$2.run(JConsole.java:404)