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List:       jakarta-commons-dev
Subject:    [jira] [Updated] (BCEL-317) Pluggable cache for ConstantUtf8
From:       "Tomo Suzuki (JIRA)" <jira () apache ! org>
Date:       2019-05-31 17:42:00
Message-ID: JIRA.13232330.1557350438000.379841.1559324520303 () Atlassian ! JIRA
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     [ https://issues.apache.org/jira/browse/BCEL-317?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel \
]

Tomo Suzuki updated BCEL-317:
-----------------------------
    Description: 
Follow-up of  BCEL-186. This enhancement is to provide an option to cache \
ConstantUtf8 instances that have the same value.

  

Email thread:  [bcel] Idea to share ConstantUtf8 of same value among JavaClass \
instances

--------------------
 We use BCEL library to inspect Java class. Thank you for the great library.
   
 When our tool checks classes in ~200 jar files, it creates more than 2 million BCEL \
ConstantUtf8 instances. I suspect many of them share the same values such as \
"java.lang.String".  

Without  cache, my tool created 2,6 million ConstantUtf8 instances (before failing \
OutOfMemoryError: GC overhead limit exceeded) to check ~200 jar files.

!2644k_constantutf8_without_getCachedInstance.png!

  

With the cache, my tool created just 0.6 million ConstantUtf8 instances. It didn't \
throw the OutOfMemoryError.

!621k_constantutf8_with_getCachedInstance.png!

  
 Old commit that made ConstantUtf8.getInstance \
[https://svn.apache.org/viewvc/commons/proper/bcel/trunk/src/main/java/org/apache/bcel/classfile/Constant.java?r1=1481383&r2=1481382&pathrev=1481383]


The ConstantUtf8.getInstance has been unused in BCEL since  BCEL-186 \
[http://svn.apache.org/viewvc/commons/proper/bcel/trunk/src/main/java/org/apache/bcel/classfile/ConstantUtf8.java?r1=1652541&r2=1652540&pathrev=1652541]


  
h1. How our project uses BCEL

Our tool (Linkage Checker) creates BCEL's ClassPathRepository with around 200 JAR \
files as its input class path \
([ClassDumper.createClassRepository|https://github.com/GoogleCloudPlatform/cloud-opens \
ource-java/blob/239fb82e368b2c181e358359f758b33c0a122787/dependencies/src/main/java/com/google/cloud/tools/opensource/classpath/ClassDumper.java#L83]) \
and reads JavaClass one by one \
([ClassDumper.listClassesInJar|https://github.com/GoogleCloudPlatform/cloud-opensource \
-java/blob/239fb82e368b2c181e358359f758b33c0a122787/dependencies/src/main/java/com/google/cloud/tools/opensource/classpath/ClassDumper.java#L360]) \
through the ClassPathRepository.

  

  

  

  was:
Follow-up of  https://issues.apache.org/jira/browse/BCEL-186. This enhancement is to \
provide an option to cache ConstantUtf8 instances that have the same value.

  

Email thread:  [bcel] Idea to share ConstantUtf8 of same value among JavaClass \
instances

--------------------
 We use BCEL library to inspect Java class. Thank you for the great library.
   
 When our tool checks classes in ~200 jar files, it creates more than 2 million BCEL \
ConstantUtf8 instances. I suspect many of them share the same values such as \
"java.lang.String".  

Without  cache, my tool created 2,6 million ConstantUtf8 instances (before failing \
OutOfMemoryError: GC overhead limit exceeded) to check ~200 jar files.

!2644k_constantutf8_without_getCachedInstance.png!

  

With the cache, my tool created just 0.6 million ConstantUtf8 instances. It didn't \
throw the OutOfMemoryError.

!621k_constantutf8_with_getCachedInstance.png!

  
 Old commit that made ConstantUtf8.getInstance \
[https://svn.apache.org/viewvc/commons/proper/bcel/trunk/src/main/java/org/apache/bcel/classfile/Constant.java?r1=1481383&r2=1481382&pathrev=1481383]


  
h1. How our project uses BCEL

Our tool (Linkage Checker) creates BCEL's ClassPathRepository with around 200 JAR \
files as its input class path \
([ClassDumper.createClassRepository|https://github.com/GoogleCloudPlatform/cloud-opens \
ource-java/blob/239fb82e368b2c181e358359f758b33c0a122787/dependencies/src/main/java/com/google/cloud/tools/opensource/classpath/ClassDumper.java#L83]) \
and reads JavaClass one by one \
([ClassDumper.listClassesInJar|https://github.com/GoogleCloudPlatform/cloud-opensource \
-java/blob/239fb82e368b2c181e358359f758b33c0a122787/dependencies/src/main/java/com/google/cloud/tools/opensource/classpath/ClassDumper.java#L360]) \
through the ClassPathRepository.

  

  

  


> Pluggable cache for ConstantUtf8
> --------------------------------
> 
> Key: BCEL-317
> URL: https://issues.apache.org/jira/browse/BCEL-317
> Project: Commons BCEL
> Issue Type: Improvement
> Components: Main
> Affects Versions: 6.3.1
> Reporter: Tomo Suzuki
> Priority: Minor
> Attachments: 2644k_constantutf8_without_getCachedInstance.png, \
> 621k_constantutf8_with_getCachedInstance.png 
> Time Spent: 10m
> Remaining Estimate: 0h
> 
> Follow-up of  BCEL-186. This enhancement is to provide an option to cache \
> ConstantUtf8 instances that have the same value. 
> Email thread:  [bcel] Idea to share ConstantUtf8 of same value among JavaClass \
>                 instances
> --------------------
> We use BCEL library to inspect Java class. Thank you for the great library.
> 
> When our tool checks classes in ~200 jar files, it creates more than 2 million BCEL \
> ConstantUtf8 instances. I suspect many of them share the same values such as \
> "java.lang.String". 
> Without  cache, my tool created 2,6 million ConstantUtf8 instances (before failing \
>                 OutOfMemoryError: GC overhead limit exceeded) to check ~200 jar \
>                 files.
> !2644k_constantutf8_without_getCachedInstance.png!
> 
> With the cache, my tool created just 0.6 million ConstantUtf8 instances. It didn't \
>                 throw the OutOfMemoryError.
> !621k_constantutf8_with_getCachedInstance.png!
> 
> Old commit that made ConstantUtf8.getInstance \
> [https://svn.apache.org/viewvc/commons/proper/bcel/trunk/src/main/java/org/apache/bcel/classfile/Constant.java?r1=1481383&r2=1481382&pathrev=1481383]
>  The ConstantUtf8.getInstance has been unused in BCEL since  BCEL-186 \
> [http://svn.apache.org/viewvc/commons/proper/bcel/trunk/src/main/java/org/apache/bcel/classfile/ConstantUtf8.java?r1=1652541&r2=1652540&pathrev=1652541]
>  
> h1. How our project uses BCEL
> Our tool (Linkage Checker) creates BCEL's ClassPathRepository with around 200 JAR \
> files as its input class path \
> ([ClassDumper.createClassRepository|https://github.com/GoogleCloudPlatform/cloud-ope \
> nsource-java/blob/239fb82e368b2c181e358359f758b33c0a122787/dependencies/src/main/java/com/google/cloud/tools/opensource/classpath/ClassDumper.java#L83]) \
> and reads JavaClass one by one \
> ([ClassDumper.listClassesInJar|https://github.com/GoogleCloudPlatform/cloud-opensour \
> ce-java/blob/239fb82e368b2c181e358359f758b33c0a122787/dependencies/src/main/java/com/google/cloud/tools/opensource/classpath/ClassDumper.java#L360]) \
> through the ClassPathRepository. 
> 
> 



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