Develop Reference

Sending over Interface Object from method call hiding implementation super class on server via RMI?

Say I have class SuperNode and an interface Node:
SuperNode implements Node
I have a RMI-Implementation server side and I'm trying to just send the Node over from a method without the user having the source file for SuperNode but they do have the interface Node.
public Node RMIImplServer.getNode();
When I do this I get this error:
java.rmi.UnmarshalException: error unmarshalling return; nested
exception is: java.lang.ClassNotFoundException:
SEHT.somepackage.SuperNode (no security manager: RMI class loader
disabled) at sun.rmi.server.UnicastRef.invoke(Unknown Source) at
java.rmi.server.RemoteObjectInvocationHandler.invokeRemoteMethod(Unknown
Source) at
java.rmi.server.RemoteObjectInvocationHandler.invoke(Unknown Source)
at com.sun.proxy.$Proxy0.getDataNodes(Unknown Source) Caused by:
java.lang.ClassNotFoundException: SEHT.somepackage.SuperNode (no
security manager: RMI class loader disabled) at
sun.rmi.server.LoaderHandler.loadClass(Unknown Source) at
sun.rmi.server.LoaderHandler.loadClass(Unknown Source) at
java.rmi.server.RMIClassLoader$2.loadClass(Unknown Source) at
java.rmi.server.RMIClassLoader.loadClass(Unknown Source) at
sun.rmi.server.MarshalInputStream.resolveClass(Unknown Source) at
java.io.ObjectInputStream.readNonProxyDesc(Unknown Source) at
java.io.ObjectInputStream.readClassDesc(Unknown Source) at
java.io.ObjectInputStream.readOrdinaryObject(Unknown Source) at
java.io.ObjectInputStream.readObject0(Unknown Source) at
java.io.ObjectInputStream.readObject(Unknown Source) at
java.util.ArrayList.readObject(Unknown Source) at
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at
sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at
sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at
java.lang.reflect.Method.invoke(Unknown Source) at
java.io.ObjectStreamClass.invokeReadObject(Unknown Source) at
java.io.ObjectInputStream.readSerialData(Unknown Source) at
java.io.ObjectInputStream.readOrdinaryObject(Unknown Source) at
java.io.ObjectInputStream.readObject0(Unknown Source) at
java.io.ObjectInputStream.readObject(Unknown Source) at
sun.rmi.server.UnicastRef.unmarshalValue(Unknown Source) ... 5 more
Is what I'm trying to do possible, if so what am I doing wrong, any help would be appreciated.
Finally figured it out...the jar file wasn't including the right files due to a stupid default that I didn't check. Thank you so much EJP for your help.

The client doesn't need any source files. It does however need the object files (.class) files for all types returned by remote methods, available on its CLASSPATH, unless:
... if you don't want to deploy SuperNode.class or whatever it is at the client, you can use the codebase feature. It's complicated.
You will need to install a security manager at the client.
You will need to define the system property java.rmi.server.codebase at the server JVM.
You will need to set it to one or more URLs that are intelligible to the client and that name JAR file(s) containing classes to be loaded dynamically. Typically a codebase item is an HTTP URL. Note that a codebase item referring to the file system local to the server cannot work, as it isn't intelligible to the client.

Java.util.PropertyPermission Failure

I'm trying to run a simple Java Web Start App. I wrote my code in NetBeans and used the jar exported for my .jnlp file. Eventually I plan on having the code read from the windows registry and use that data, but for now all I'm doing is creating a String then calling System.out.println(strName); I am self signing the jar using the strategy outlined here. When I download and run the .jnlp, I get the following exception:
java.security.AccessControlException: access denied ("java.util.PropertyPermission" "jna.debug_load" "read")
at java.security.AccessControlContext.checkPermission(Unknown Source)
at java.security.AccessController.checkPermission(Unknown Source)
at java.lang.SecurityManager.checkPermission(Unknown Source)
at com.sun.javaws.security.JavaWebStartSecurity.checkPermission(Unknown Source)
at java.lang.SecurityManager.checkPropertyAccess(Unknown Source)
at java.lang.System.getProperty(Unknown Source)
at java.lang.Boolean.getBoolean(Unknown Source)
at com.sun.jna.Native.<clinit>(Native.java:95)
at com.sun.jna.Pointer.<clinit>(Pointer.java:41)
at com.sun.jna.platform.win32.WinReg$HKEY.<init>(WinReg.java:32)
at com.sun.jna.platform.win32.WinReg.<clinit>(WinReg.java:61)
at cvbxtractor.CvbXtractor.main(CvbXtractor.java:17)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.sun.javaws.Launcher.executeApplication(Unknown Source)
at com.sun.javaws.Launcher.executeMainClass(Unknown Source)
at com.sun.javaws.Launcher.doLaunchApp(Unknown Source)
at com.sun.javaws.Launcher.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
I have tried adding permission java.util.PropertyPermission "jna.debug_load", "read"; to my java.policy file, I have tried signing and resigning any jars it might be using, and made sure my .jnlp has the
<security>
<all-permissions/>
</security>
line in it, but none have helped. I'm sure I'm just missing some security toggle somewhere, if this is easy please forgive me, this is my first Java Web Start App.

As of java 7u45, you can't read system properties when running from a jnlp. Oracle basically ruined javaws. If you're writing a new app, I would recommend staying away from java webstart. It's broken and they just keep making it worse by forcing security updates that break your application.
That being said, one partial workaround to this problem is to prefix all of your properties with jnlp.. So, you'd have to rename your property jnlp.jna.debug_load. If it's a property from a third party library/jar you're using, you're out of luck.

Error in running startNetworkServer

I am trying to start the network server from outside netbeans. I did set the DERBY_INSTALL variable to the appropriate directory, then i issue setNetworkServerCP command which also works fine. But when i try to run startNetworkServer i am getting the following error.
C:\Users\tandons>D:
D:>cd D:\netbeans\glassfish-v2.1\javadb\bin
D:\netbeans\glassfish-v2.1\javadb\bin>setNetworkServerCP DERBY_HOME or
DERBY_INSTALL not set. Set one of these variables to the location of
your Derby installation. D:\netbeans\glassfish-v2.1\javadb\bin>set
DERBY_INSTALL=D:\netbeans\glassfish-v2 .1\javadb
D:\netbeans\glassfish-v2.1\javadb\bin>setNetworkServerCP.bat
D:\netbeans\glassfish-v2.1\javadb\bin>SET
DERBY_INSTALL=D:\netbeans\GLASSF~1.1\j avadb
D:\netbeans\glassfish-v2.1\javadb\bin>set
CLASSPATH=D:\netbeans\glassfish-v2.1\j
avadb\lib\derbynet.jar;D:\netbeans\glassfish-v2.1\javadb\lib\derbytools.jar;
D:\netbeans\glassfish-v2.1\javadb\bin>setNetworkServerCP
D:\netbeans\glassfish-v2.1\javadb\bin>SET
DERBY_INSTALL=D:\netbeans\GLASSF~1.1\j avadb
D:\netbeans\glassfish-v2.1\javadb\bin>set
CLASSPATH=D:\netbeans\glassfish-v2.1\j
avadb\lib\derbynet.jar;D:\netbeans\glassfish-v2.1\javadb\lib\derbytools.jar;D:\n
etbeans\glassfish-v2.1\javadb\lib\derbynet.jar;D:\netbeans\glassfish-v2.1\javadb
\lib\derbytools.jar;
D:\netbeans\glassfish-v2.1\javadb\bin>startNetworkServer Security
manager installed using the Basic server security policy. access
denied ("java.net.SocketPermission" "localhost:1527" "listen,resolve")
java.security.AccessControlException: access denied
("java.net.SocketPermission" "localhost:1527" "listen,resolve")
at java.security.AccessControlContext.checkPermission(Unknown Source)
at java.security.AccessController.checkPermission(Unknown Source)
at java.lang.SecurityManager.checkPermission(Unknown Source)
at java.lang.SecurityManager.checkListen(Unknown Source)
at java.net.ServerSocket.bind(Unknown Source)
at java.net.ServerSocket.(Unknown Source)
at javax.net.DefaultServerSocketFactory.createServerSocket(Unknown Sourc
e)
at org.apache.derby.impl.drda.NetworkServerControlImpl.createServerSocke
t(Unknown Source)
at org.apache.derby.impl.drda.NetworkServerControlImpl.access$000(Unknow
n Source)
at org.apache.derby.impl.drda.NetworkServerControlImpl$1.run(Unknown Sou
rce)
at java.security.AccessController.doPrivileged(Native Method)
at org.apache.derby.impl.drda.NetworkServerControlImpl.blockingStart(Unk
nown Source)
at org.apache.derby.impl.drda.NetworkServerControlImpl.executeWork(Unkno
wn Source)
at org.apache.derby.drda.NetworkServerControl.main(Unknown Source)
D:\netbeans\glassfish-v2.1\javadb\bin>
also is there a better way to do this from within a java program. I read the official doc given on Apache website( using NetworkServerControl api ) but i can make hardly anything out of whats given there..........

This is a known bug. Workarounds are described in the links below. (Google is your friend):
Netbeans bug report
Blog 1
Blog 2

RMI exception. Cannot connect to the server

I'm trying to connect a client and remote server through RMI and I get this error message:
java.rmi.UnmarshalException: error unmarshalling return; nested exception is:
java.net.MalformedURLException: unknown protocol: c
at sun.rmi.registry.RegistryImpl_Stub.lookup(Unknown Source)
at java.rmi.Naming.lookup(Unknown Source)
at RmiClient.getMessage(RmiClient.java:11)
at RmiClient.main(RmiClient.java:26)
Caused by: java.net.MalformedURLException: unknown protocol: c
at java.net.URL.<init>(Unknown Source)
at java.net.URL.<init>(Unknown Source)
at java.net.URL.<init>(Unknown Source)
at sun.rmi.server.LoaderHandler.pathToURLs(Unknown Source)
at sun.rmi.server.LoaderHandler.getDefaultCodebaseURLs(Unknown Source)
at sun.rmi.server.LoaderHandler.loadClass(Unknown Source)
at java.rmi.server.RMIClassLoader$2.loadClass(Unknown Source)
at java.rmi.server.RMIClassLoader.loadClass(Unknown Source)
at sun.rmi.server.MarshalInputStream.resolveClass(Unknown Source)
at java.io.ObjectInputStream.readNonProxyDesc(Unknown Source)
at java.io.ObjectInputStream.readClassDesc(Unknown Source)
at java.io.ObjectInputStream.readOrdinaryObject(Unknown Source)
at java.io.ObjectInputStream.readObject0(Unknown Source)
at java.io.ObjectInputStream.readObject(Unknown Source)
... 4 more
The following may be the cause of the problem:
The server has this line:
Naming.rebind("rmi://172.31.24.66:1099/RmiServer", obj);
which refers to the private IP address of an EC2 instance. The client on the other hand has this line - which is line 11 from above:
RmiServerIntf obj = (RmiServerIntf)Naming.lookup("rmi://54.229.66.114:1099/RmiServer");
which is the public IP of that instance. Also, on the client side I set the codebase property as:
System.setProperty("java.rmi.server.codebase", "C:\\Users\\spacitron\\Projects\\RMIClient\\bin");
If I try to add the same line on the server I get a "permission denied" error.

A codebase is a list of URLs. What you have specified is a file name, not a URL.
It is also a rather useless filename, unless the client is on the same host as the server, in which case it is difficult to see why you're using the codebase feature at all. Even if you have a shared drive it is just as easy to specify directories in the client's CLASSPATH as it is to use java.rmi.server.codebase. A codebase URL needs to be usable by the recipient. That's why they are almost always HTTP URLs, or maybe FTP URLs.

try down grading your jdk7 below update 21/jdk6 below update 45.
compile and test again of this work problem is java.rmi.server.useCodebaseOnly system property
please check below link for solution for both version of jdk's
http://docs.oracle.com/javase/7/docs/technotes/guides/rmi/relnotes.html

Trouble with Java Web Start

Trying to run my program through java web start. I get the following exception in the output console. Im new to java web start so do any of you have any ideas?
FYI, here is line 66
ConfigFileReader cfg = new ConfigFileReader(BCApp.getConfigFileLocation());
java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.sun.javaws.Launcher.executeApplication(Unknown Source)
at com.sun.javaws.Launcher.executeMainClass(Unknown Source)
at com.sun.javaws.Launcher.doLaunchApp(Unknown Source)
at com.sun.javaws.Launcher.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.ExceptionInInitializerError
at JCS.Main$setStyle.setStyle(Main.java:66)
at JCS.Main.main(Main.java:57)
... 9 more
Caused by: java.security.AccessControlException: access denied (java.util.PropertyPermission java.io.tmpdir read)
at java.security.AccessControlContext.checkPermission(Unknown Source)
at java.security.AccessController.checkPermission(Unknown Source)
at java.lang.SecurityManager.checkPermission(Unknown Source)
at java.lang.SecurityManager.checkPropertyAccess(Unknown Source)
at java.lang.System.getProperty(Unknown Source)
at GUI.BCApp.(BCApp.java:60)
... 11 more

You are going to want to read up on the security manager. Because code launched through Java Web Start could potentially cause grave harm to client computers there are a lot of things it is usually not allowed to do. File system access is one of them. There are several ways to enable your Java Web Start app to access the file system detailed in the documentation.

Your WS application runs from a security sandbox environment, which means it doesn't have an access to the file system, unless a) your app is digitally signed or b) you can modify your security settings (which is not recommended btw).