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https://issues.apache.org/jira/browse/HADOOP-13070?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Sangjin Lee updated HADOOP-13070:
---------------------------------
Attachment: lib.jar
Test.java
TestDriver.java
HADOOP-13070.poc.01.patch
Posted a POC patch that illustrates the idea on how we might prevent a user
caller class from loading classes from the parent classpath. This is admittedly
a very preliminary version.
I also attached a quick test driver to test out the idea. You can save them to
a directory structure like
{noformat}
- driver/TestDriver.java
- lib.jar
- user/Test.java
{noformat}
{{Test.java}} tries to load {{foo.Foo}} (in {{lib.jar}}) via various ways of
classloading (you can uncomment and comment those approaches in {{Test.java}}
to test each). You can place {{lib.jar}} either in the main classpath ("parent"
classpath) or as an argument to {{TestDriver}} ("user" classpath) and see what
happens. For example,
{noformat}
java -cp
/Users/alice/git/hadoop-trunk/hadoop-common-project/hadoop-common/target/hadoop-common-3.0.0-alpha1-SNAPSHOT.jar:/Users/alice/.m2/repository/commons-logging/commons-logging/1.2/commons-logging-1.2.jar:/Users/alice/.m2/repository/org/slf4j/slf4j-api/1.7.7/slf4j-api-1.7.7.jar:.
TestDriver ../user:../lib.jar
{noformat}
or
{noformat}
java -cp
/Users/alice/git/hadoop-trunk/hadoop-common-project/hadoop-common/target/hadoop-common-3.0.0-alpha1-SNAPSHOT.jar:/Users/alice/.m2/repository/commons-logging/commons-logging/1.2/commons-logging-1.2.jar:/Users/alice/.m2/repository/org/slf4j/slf4j-api/1.7.7/slf4j-api-1.7.7.jar:.:../lib.jar
TestDriver ../user
{noformat}
> classloading isolation improvements for cleaner and stricter dependencies
> -------------------------------------------------------------------------
>
> Key: HADOOP-13070
> URL: https://issues.apache.org/jira/browse/HADOOP-13070
> Project: Hadoop Common
> Issue Type: Improvement
> Components: util
> Reporter: Sangjin Lee
> Assignee: Sangjin Lee
> Priority: Critical
> Attachments: HADOOP-13070.poc.01.patch, Test.java, TestDriver.java,
> classloading-improvements-ideas-v.3.pdf, classloading-improvements-ideas.pdf,
> classloading-improvements-ideas.v.2.pdf, lib.jar
>
>
> Related to HADOOP-11656, we would like to make a number of improvements in
> terms of classloading isolation so that user-code can run safely without
> worrying about dependency collisions with the Hadoop dependencies.
> By the same token, it should raised the quality of the user code and its
> specified classpath so that users get clear signals if they specify incorrect
> classpaths.
> This will contain a proposal that will include several improvements some of
> which may not be backward compatible. As such, it should be targeted to the
> next major revision of Hadoop.
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