RCP application cannot start due to OSGi package dependency problem

Question

We use both spring-web and spring-websocket in our RCP application, which both are converted into packages via p2-maven-plugin.The following is the MANIFEST.MF file of our application.

 Manifest-Version: 1.0 Bundle-ManifestVersion: 2 Bundle-Name: Todo Bundle-SymbolicName: com.example.e4.rcp.todo;singleton:=true Bundle-Version: 1.0.0.qualifier Bundle-Vendor: EXAMPLE Bundle-RequiredExecutionEnvironment: JavaSE-1.8 Require-Bundle: org.apache.commons.logging;bundle-version="1.2.0", org.springframework.spring-aop;bundle-version="4.3.3", org.springframework.spring-beans;bundle-version="4.3.3", org.springframework.spring-context;bundle-version="4.3.3", org.springframework.spring-core;bundle-version="4.3.3", org.springframework.spring-expression;bundle-version="4.3.3", org.springframework.spring-web;bundle-version="4.3.3", org.eclipse.e4.ui.css.swt;bundle-version="0.12.0", org.eclipse.e4.ui.css.swt.theme;bundle-version="0.10.0", org.eclipse.e4.ui.workbench.addons.swt;bundle-version="1.2.0", org.eclipse.e4.ui.workbench.renderers.swt;bundle-version="0.13.0", org.eclipse.e4.ui.workbench.swt;bundle-version="0.13.0", org.eclipse.swt;bundle-version="3.104.1", org.eclipse.e4.ui.di;bundle-version="1.1.0", org.eclipse.e4.core.services;bundle-version="2.0.100", org.eclipse.osgi.services;bundle-version="3.5.100", org.eclipse.e4.core.di.annotations;bundle-version="1.5.0", org.springframework.spring-websocket;bundle-version="4.3.2", org.springframework.spring-messaging;bundle-version="4.3.2", javax.inject;bundle-version="1.0.0", javax.annotation;bundle-version="1.2.0", org.apache.tomcat.embed.tomcat-embed-core;bundle-version="8.5.4", org.apache.tomcat.embed.tomcat-embed-websocket;bundle-version="8.5.4" 

When I launch the application, it gives the following error:

  !SESSION 2016-11-10 09:48:03.750 ----------------------------------------------- eclipse.buildId=unknown java.version=1.8.0_101 java.vendor=Oracle Corporation BootLoader constants: OS=win32, ARCH=x86_64, WS=win32, NL=en_US Framework arguments: -product com.example.e4.rcp.todo.product clearPersistedState Command-line arguments: -product com.example.e4.rcp.todo.product -data > :\Users\wangzen\Console_prototype/../runtime-todo.product -dev > ile:C:/Users/wangzen/Console_prototype/.metadata/.plugins/org.eclipse.pde.core/to> o.product/dev.properties -os win32 -ws win32 -arch x86_64 -consoleLog > clearPersistedState !ENTRY org.eclipse.equinox.app 0 0 2016-11-10 09:48:04.703 !MESSAGE Product com.example.e4.rcp.todo.product could not be found. !ENTRY com.example.e4.rcp.todo 2 0 2016-11-10 09:48:04.786 !MESSAGE Could not resolve module: com.example.e4.rcp.todo [491] Bundle was not resolved because of a uses contraint violation. org.osgi.service.resolver.ResolutionException: Uses constraint violation. nable> to resolve resource com.example.e4.rcp.todo [osgi.identity;> sgi.identity="com.example.e4.rcp.todo"; type="osgi.bundle";> ersion:Version="1.0.0.qualifier"; singleton:="true"] because it is exposed to> ackage 'javax.servlet' from resources rg.apache.tomcat.embed.tomcat-embed-core> [osgi.identity; type="osgi.bundle"; ersion:Version="8.5.4";> sgi.identity="org.apache.tomcat.embed.tomcat-embed-core"] and javax.servlet> osgi.identity; type="osgi.bundle"; version:Version="3.1.0.v201410161800";> sgi.identity="javax.servlet"] via two dependency chains. Chain 1: com.example.e4.rcp.todo [osgi.identity; sgi.identity="com.example.e4.rcp.todo";> type="osgi.bundle"; ersion:Version="1.0.0.qualifier"; singleton:="true"] require:> &(osgi.wiring.bundle=org.apache.tomcat.embed.tomcat-embed-core)(bundle-versio> >=8.5.4)) | provide: osgi.wiring.bundle: org.apache.tomcat.embed.tomcat-embed-core org.apache.tomcat.embed.tomcat-embed-core [osgi.identity; ype="osgi.bundle";> version:Version="8.5.4";> sgi.identity="org.apache.tomcat.embed.tomcat-embed-core"] Chain 2: com.example.e4.rcp.todo [osgi.identity; sgi.identity="com.example.e4.rcp.todo";> type="osgi.bundle"; ersion:Version="1.0.0.qualifier"; singleton:="true"] require:> &(osgi.wiring.bundle=org.springframework.spring-web)(bundle-version>=4.3.3)) | provide: osgi.wiring.bundle; bundle-version:Version="4.3.3.RELEASE";> sgi.wiring.bundle="org.springframework.spring-web" org.springframework.spring-web [osgi.identity; type="osgi.bundle";> ersion:Version="4.3.3.RELEASE"; osgi.identity="org.springframework.spring-web"] import: (osgi.wiring.package=javax.servlet) | export: osgi.wiring.package: javax.servlet javax.servlet [osgi.identity; type="osgi.bundle";> ersion:Version="3.1.0.v201410161800"; osgi.identity="javax.servlet"] !ENTRY org.eclipse.osgi 4 0 2016-11-10 09:48:04.787 !MESSAGE Application error !STACK 1 java.lang.RuntimeException: No application id has been found. at org.eclipse.equinox.internal.app.EclipseAppContainer.startDefaultApp(EclipseAppContainer.java:242) at org.eclipse.equinox.internal.app.MainApplicationLauncher.run(MainApplicationLauncher.java:29) at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:134) at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:104) at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:388) at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:243) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:673) at org.eclipse.equinox.launcher.Main.basicRun(Main.java:610) at org.eclipse.equinox.launcher.Main.run(Main.java:1519) at org.eclipse.equinox.launcher.Main.main(Main.java:1492) gogo: InterruptedException: sleep interrupted java.lang.InterruptedException: sleep interrupted at java.lang.Thread.sleep(Native Method) at org.apache.felix.gogo.shell.Activator.run(Activator.java:72) at java.lang.Thread.run(Thread.java:745) An error has occurred. See the log file C:\Users\wangzen\runtime-todo.product\.metadata\.log. 

The problem seems to be related to the fact that both org.apache.tomcat.embed.tomcat-embed-core and org.springframework.spring-web have a dependency chain up to javax.servlet . However, after I removed the tomcat libraries, it tells me another error, as shown below:

 java.lang.NoClassDefFoundError: org/apache/tomcat/InstanceManagerBindings at org.apache.tomcat.websocket.WsSession.<init>(WsSession.java:187) at org.apache.tomcat.websocket.WsWebSocketContainer.connectToServer(WsWebSocketContainer.java:403) at org.springframework.web.socket.client.standard.StandardWebSocketClient$1.call(StandardWebSocketClient.java:150) at org.springframework.web.socket.client.standard.StandardWebSocketClient$1.call(StandardWebSocketClient.java:147) at java.util.concurrent.FutureTask.run(FutureTask.java:266) at java.lang.Thread.run(Thread.java:745) Caused by: java.lang.ClassNotFoundException: org.apache.tomcat.InstanceManagerBindings cannot be found by org.apache.tomcat.embed.tomcat-embed-websocket_8.5.4 at org.eclipse.osgi.internal.loader.BundleLoader.findClassInternal(BundleLoader.java:448) at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:361) at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:353) at org.eclipse.osgi.internal.loader.ModuleClassLoader.loadClass(ModuleClassLoader.java:161) at java.lang.ClassLoader.loadClass(ClassLoader.java:357) 

UPDATE

What I tried:

• Checking the dependencies on the Eclipse plug-in Dependencies tool shown in the following screenshot, I found that org.apache.tomcat.embed.tomcat-embed-core and org.apache.tomcat.embed.tomcat-embed-websocket can not needed for my application, so I uninstalled these two packages and restarted my application.

However, another error message appears, as shown below:

 java.lang.NoClassDefFoundError: org/apache/tomcat/InstanceManagerBindings at org.apache.tomcat.websocket.WsSession.<init>(WsSession.java:187) at org.apache.tomcat.websocket.WsWebSocketContainer.connectToServer(WsWebSocketContainer.java:403) at org.springframework.web.socket.client.standard.StandardWebSocketClient$1.call(StandardWebSocketClient.java:150) at org.springframework.web.socket.client.standard.StandardWebSocketClient$1.call(StandardWebSocketClient.java:147) at java.util.concurrent.FutureTask.run(FutureTask.java:266) at java.lang.Thread.run(Thread.java:745) Caused by: java.lang.ClassNotFoundException: org.apache.tomcat.InstanceManagerBindings cannot be found by org.apache.tomcat.embed.tomcat-embed-websocket_8.5.4 at org.eclipse.osgi.internal.loader.BundleLoader.findClassInternal(BundleLoader.java:448) at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:361) at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:353) at org.eclipse.osgi.internal.loader.ModuleClassLoader.loadClass(ModuleClassLoader.java:161) at java.lang.ClassLoader.loadClass(ClassLoader.java:357) ... 6 more 

• I also tried replacing Require-Bundle with Import-Package when importing these third-party libraries as follows:

   Manifest-Version: 1.0 Bundle-ManifestVersion: 2 Bundle-Name: Todo Bundle-SymbolicName: com.example.e4.rcp.todo;singleton:=true Bundle-Version: 1.0.0.qualifier Bundle-Vendor: EXAMPLE Bundle-RequiredExecutionEnvironment: JavaSE-1.8 Require-Bundle: org.eclipse.e4.ui.css.swt;bundle-version="0.12.0", org.eclipse.e4.ui.css.swt.theme;bundle-version="0.10.0", org.eclipse.e4.ui.workbench.addons.swt;bundle-version="1.2.0", org.eclipse.e4.ui.workbench.renderers.swt;bundle-version="0.13.0", org.eclipse.e4.ui.workbench.swt;bundle-version="0.13.0", org.eclipse.swt;bundle-version="3.104.1", org.eclipse.e4.ui.di;bundle-version="1.1.0", org.eclipse.e4.core.services;bundle-version="2.0.100", org.eclipse.osgi.services;bundle-version="3.5.100", org.eclipse.e4.core.di.annotations;bundle-version="1.5.0", javax.inject;bundle-version="1.0.0", javax.annotation;bundle-version="1.2.0" Import-Package: org.apache.tomcat, org.springframework.http, org.springframework.http.client, org.springframework.http.client.support, org.springframework.messaging.converter, org.springframework.messaging.simp.stomp, org.springframework.scheduling, org.springframework.scheduling.concurrent, org.springframework.util, org.springframework.web.client, org.springframework.web.socket.client, org.springframework.web.socket.client.standard, org.springframework.web.socket.messaging, org.springframework.web.socket.sockjs.client 

However, it still pops up with the same error, let me know that org.apache.tomcat.InstanceManagerBindings cannot be found by org.apache.tomcat.embed.tomcat-embed-websocket_8.5.4

Answer 1

Here you are faced with several problems. The first is that you use the required package all over the place. The problem with bundling is that you are always exposed to all the packages that packages offer. This will increase the likelihood of using chain restriction violations. Instead, try using Import-Package.

Another problem is that spring no longer supports OSGi. Therefore, using spring libraries in OSGi is likely to cause problems because they simply do not test their code in OSGi.

If you need websocket support, pax web might be the best choice. It works with tomcat or jetty and wraps them in an OSGi compatible way.

Unfortunately, there is no example for pax-web or a simple jetty for an eclipse. To find out which packages you need, you can run apache karaf and install the http function. Then you can examine the packages that it installs and use them in eclipse rcp.

Answer 2

Add version information to your javax.servlet import package so that OSGi can decide which dependency chain to use.

 javax.servlet;version="3.1.0"