Fix (APAR):  PI69918

Status:  Fix

Release:  8.5.5.11,8.5.5.10,8.5.5.9,8.5.5.8,8.5.5.7,8.5.5.6,8.5.5.5,8.5.5.4,8.5.5.3,8.5.5.2,8.5.5.1,8.5.5

Operating System:  AIX,HP-UX,IBM i,Inspur K-UX,Linux,OS X,Solaris,Windows,iOS,z/OS

Supersedes Fixes:  

CMVC Defect:  xxxxxx

Byte size of APAR:  267766

Date: 2017-03-22

Abstract:  synchronization issue in the ebaclassloader causes osgi application startup to fail due to java.lang.linkageerror

Description/symptom of problem:  
PI69918 resolves the following problem:

ERROR DESCRIPTION:                                              
OSGi Application fails to start due to java.lang.LinkageError   
during EBAClassLoader.loadClass method.                         
                                                                
An example error message and partial call stack is shown below: 
                                                                
BundleStartTa E   CWSAH0011E: An internal error occurred. The   
runtime environment could not start the web bundle              
com.ibm.example.service.ejb_11.6.0.201608191312 because of      
exception java.lang.LinkageError:                               
com.ibm.ws.eba.equinox.classloading.                            
Java2PermissionsRepository                                      
 at java.lang.ClassLoader.defineClassImpl(Native Method)        
 at java.lang.ClassLoader.defineClass(ClassLoader.java:349)     
 at java.security.SecureClassLoader.defineClass(                
SecureClassLoader.java: 154)                                    
 at java.net.URLClassLoader.defineClass(                        
URLClassLoader.java:727)                                        
 at java.net.URLClassLoader.access$400(URLClassLoader.java:95)  
 at java.net.URLClassLoader$ClassFinder.run(                    
URLClassLoader.java:1182)                                       
 at java.security.AccessController.doPrivileged(                
AccessController.java:686)                                      
 at java.net.URLClassLoader.findClass(URLClassLoader.java:602)  
 at com.ibm.ws.eba.internal.framework.EBAClassLoader.loadClass  
(EBAClassLoader.java:105)                                       
...                                                             
                                                                

LOCAL FIX:                                                      
N/A                                                             

PROBLEM SUMMARY

USERS AFFECTED:
 WebSphere Application Server users of OSGi
applications

PROBLEM DESCRIPTION:
OSGi application fails to start due
to java.lang.LinkageError

RECOMMENDATION:
None

The EBAClassLoader follows the standard class loading pattern
of calling findLoadedClass to determine if the class has
already been loaded and if it is not already loaded it attempts
to load the class.  The error occurred when two threads
concurrently requested the same class to be loaded.  A lack
of synchronization in the EBAClassLoader.loadClass method
meant that both threads determined that the class needed to be
loaded.  When the second thread loaded the class it had
already been loaded and the JVM threw the
java.lang.LinkageError to indicate the condition.

PROBLEM CONCLUSION:                                             
Synchronization was added to the EBAClassLoader.loadClass       
method.                                                         
                                                                
The fix for this APAR is currently targeted for inclusion in    
fix pack 8.5.5.12.  Please refer to the Recommended Updates     
page for delivery information:                                  
http://www.ibm.com/support/docview.wss?rs=180&uid=swg27004980   


Directions to apply fix:  Fix applies to Editions:
Release 8.5
_x_ Application Server (Express or BASE)
_x_ Network Deployment (ND)
__ Liberty Core
__ Edge Components
__ Developer

Install Fix to all WebSphere installations unless special instructions are included below.

Special Instructions: None

NOTE:
The user must:
* Logged in with the same authority level when unpacking a fix, fix pack or refresh pack.
* Be at V1.4.3 or newer of the Installation Manager. Certain iFixes may require a newer version of the Installation Manager and the Installation Manager will inform you during the installation process if a newer version is required.

The IBM Knowledge Center can provide details, if needed, on the use of the Installation Manager to apply the iFixes.
http://publib.boulder.ibm.com/infocenter/install/v1r4/index.jsp.  Shutdown WebSphere Application Server before applying the iFixes.  Restart WebSphere Application Server after applying the iFixes.

Directions to remove fix:  

The IBM Knowledge Center can provide details, if needed, on the use of the Installation Manager to remove the iFixes.
http://publib.boulder.ibm.com/infocenter/install/v1r4/index.jsp.  Shutdown WebSphere Application Server before removing the iFixes.  Restart WebSphere Application Server after removing the iFixes.

Directions to re-apply fix:  
1) Shutdown WebSphere Application Server.

2) Follow the Fix instructions to apply the fix.

3) Restart WebSphere Application Server.



Additional Information: