Re: [mat-dev] IBM DTFJ Feature update will require Java 1.8

[Pete Robbins <ROBBINS@xxxxxxxxxx>]

Andrew,

thanks for that. It's
good that we won't break the MAT builds. 

I was looking for a way to prevent the DTFJ
feature installing if you were running with Java 1.7 but even specifying

Bundle-RequiredExecutionEnvironment:
JavaSE-1.8
in the plugins only ensures that the underlying
eclipse can support Java 1.8.

So what happens now if I am eg running MAT
(Mars) on Java 1.7 and install the updated DTFJ feature? Well when trying
to open an IBM core file you get:

>>
No parser registered for file

Error while creating IIndexBuilder 'indexBuilder'
org.eclipse.core.runtime.CoreException: Plug-in
"org.eclipse.mat.dtfj" was unable to instantiate class "org.eclipse.mat.dtfj.DTFJIndexBuilder".
        at org.eclipse.core.internal.registry.osgi.RegistryStrategyOSGI.throwException(RegistryStrategyOSGI.java:194)
        at org.eclipse.core.internal.registry.osgi.RegistryStrategyOSGI.createExecutableExtension(RegistryStrategyOSGI.java:188)
        at org.eclipse.core.internal.registry.ExtensionRegistry.createExecutableExtension(ExtensionRegistry.java:905)
        at org.eclipse.core.internal.registry.ConfigurationElement.createExecutableExtension(ConfigurationElement.java:243)
        at org.eclipse.core.internal.registry.ConfigurationElementHandle.createExecutableExtension(ConfigurationElementHandle.java:55)
        at org.eclipse.mat.parser.internal.util.ParserRegistry$Parser.create(ParserRegistry.java:85)
        at org.eclipse.mat.parser.internal.SnapshotFactoryImpl.parse(SnapshotFactoryImpl.java:196)
        at org.eclipse.mat.parser.internal.SnapshotFactoryImpl.openSnapshot(SnapshotFactoryImpl.java:126)
        at org.eclipse.mat.snapshot.SnapshotFactory.openSnapshot(SnapshotFactory.java:145)
        at org.eclipse.mat.ui.snapshot.ParseHeapDumpJob.run(ParseHeapDumpJob.java:83)
        at org.eclipse.core.internal.jobs.Worker.run(Worker.java:55)
Caused by: java.lang.UnsupportedClassVersionError:
JVMCFRE003 bad major version; class=com/ibm/dtfj/image/CorruptDataException,
offset=6
<<

I'll see if I can get a more obvious exception
thrown. I don't want to have a pre-req MAT change.

Cheers,

Peter G (Pete) Robbins
IBM Runtime Technologies

Phone: 44-1962-818667 E-mail: ROBBINS@xxxxxxxxxx IBM Monitoring and Diagnostic Tools: www.ibm.com/developerworks/java/jdk/tools/ Find me on:	Hursley Park Hursley, SO212JN United Kingdom

From:      
 Andrew Johnson <andrew_johnson@xxxxxxxxxx>
To:      
 Memory Analyzer Dev
list <mat-dev@xxxxxxxxxxx>
Date:      
 05/09/2017 16:24
Subject:    
   Re: [mat-dev]
IBM DTFJ Feature update will require Java 1.8
Sent by:    
   mat-dev-bounces@xxxxxxxxxxx

---

Pete, 

Currently we build on Hudson at Eclipse.org with jdk1.8.0-latest
The build does run tests of MAT using DTFJ so that should still work.

We currently build MAT against Eclipse Mars - see parent/pom.xml, so as
Mars has a 1.7 requirement then so does MAT. We did put a version check
into the configuration a few releases ago, but I think this was just for
Java 1.6, and if you point use Java 1.6 with MAT the check passes, so it
then fails with a strange error message. 

See 427081: Create stand-alone MAT based on Kepler (4.3)
https://bugs.eclipse.org/bugs/show_bug.cgi?id=427081#c7
https://bugs.eclipse.org/bugs/show_bug.cgi?id=427081#c8

for the settings which enforced the 1.6 check. 

There was some work done on getting MAT standalone to build using Neon.
496550: Enable building RCPs with Neon 
https://bugs.eclipse.org/bugs/show_bug.cgi?id=496550

497129: SWTBot test failures with Eclipse Neon in org.eclipse.mat.ui.rcp.tests.MemoryAnalyzerProductTest
https://bugs.eclipse.org/bugs/show_bug.cgi?id=497129

though bug 496550 has a comment: "Neon puts a requirement on java
1.8, so I would probably leave the (MAT) 1.6 packages based on an older
one." 

See also this for details of problems switching to Neon or Oxygen. This
also changes the platform support - dropping a few and adding others, e.g.
Neon Solaris is 64-bit only due to a lack of 32-bit Java 1.8 on Solaris.
For Oxygen, Eclipse has dropped support for the following Unix based platforms:
AIX, Solaris, HP-UX and s390 (and Linux PPC32), 
https://dev.eclipse.org/mhonarc/lists/mat-dev/msg00493.html

If MAT is installed into Oxygen then Oxygen already has a Java 1.8 requirement.

There is also this bug: 
520963: Building MAT on older versions of Eclipse such as 3.6/Helios
https://bugs.eclipse.org/bugs/show_bug.cgi?id=520963

Changing the DTFJ update site might be possible for two versions, but would
cause confusion and also MAT 1.7 now comes with a link to the current update
site. 

In conclusion: 
1. I think the MAT builds will succeed with the new version of DTFJ
2. We should have a Java version check for 1.7 for MAT
3. Will there be a helpful error message if running DTFJ and MAT under
Java 1.7? 
4. We may need to update some project pages / forums / wiki to explain
about the Java 1.8 requirement for DTFJ 
5. We should investigate further building standalone MAT against Neon (or
Oxygen), but check the download stats for the effect on people of removing
some platform support. 


Andrew Johnson 




From:        Pete
Robbins <ROBBINS@xxxxxxxxxx> 
To:        Memory
Analyzer Dev list <mat-dev@xxxxxxxxxxx> 
Date:        31/08/2017
10:26 
Subject:        [mat-dev]
IBM DTFJ Feature update will require Java 1.8 
Sent by:        mat-dev-bounces@xxxxxxxxxxx

---

In the next few weeks we will be updating the IBM DTFJ Feature with support
for recent IBM SDKs. This has a requirement to run on Java 1.8 (IBM or
OpenJDK). 

Will this change break MAT builds? Do you build with 1.8 or 1.7? 

It may be possible to leave the current DTFJ Feature repo where it is and
create a parallel one for the update and document how to install the new
support. 

Any thoughts? 



Cheers, 

Peter G (Pete) Robbins
IBM Runtime Technologies

Phone: 44-1962-818667 E-mail: ROBBINS@xxxxxxxxxx IBM Monitoring and Diagnostic Tools: www.ibm.com/developerworks/java/jdk/tools/ Find me on:	Hursley Park Hursley, SO212JN United Kingdom

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Unless stated otherwise above:
IBM United Kingdom Limited - Registered in England and Wales with number
741598. 
Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6
3AU