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jhades standalone report

Java classpath troubleshooting tool

License

License
GroupId

GroupId

org.jhades
ArtifactId

ArtifactId

jhades-standalone-report
Last Version

Last Version

1.0.4
Release Date

Release Date
Type

Type

jar
Description

Description

jhades standalone report
Java classpath troubleshooting tool
Project URL

Project URL

http://jhades.org/jhades-standalone-report

Download jhades-standalone-report

Filename Size
jhades-standalone-report-1.0.4.pom
jhades-standalone-report-1.0.4.jar 46 KB
jhades-standalone-report-1.0.4-sources.jar 3 KB
jhades-standalone-report-1.0.4-javadoc.jar 39 KB
Browse

How to add to project

<!-- https://jarcasting.com/artifacts/org.jhades/jhades-standalone-report/ -->
<dependency>
    <groupId>org.jhades</groupId>
    <artifactId>jhades-standalone-report</artifactId>
    <version>1.0.4</version>
</dependency>
// https://jarcasting.com/artifacts/org.jhades/jhades-standalone-report/
implementation 'org.jhades:jhades-standalone-report:1.0.4'
// https://jarcasting.com/artifacts/org.jhades/jhades-standalone-report/
implementation ("org.jhades:jhades-standalone-report:1.0.4")
'org.jhades:jhades-standalone-report:jar:1.0.4'
<dependency org="org.jhades" name="jhades-standalone-report" rev="1.0.4">
  <artifact name="jhades-standalone-report" type="jar" />
</dependency>
@Grapes(
@Grab(group='org.jhades', module='jhades-standalone-report', version='1.0.4')
)
libraryDependencies += "org.jhades" % "jhades-standalone-report" % "1.0.4"
[org.jhades/jhades-standalone-report "1.0.4"]

Dependencies

There are no dependencies for this project. It is a standalone project that does not depend on any other jars.

Project Modules

There are no modules declared in this project.

JHades - Your way out of Jar Hell!

JHades is a Java classpath troubleshooting tool. It helps to solve common Java classpath / Jar Hell related problems such as ClassNotFoundException, NoClassDefFoundError, ClassCastException, NoSuchMethodException, LinkageError, etc.

It allows to query the classpath for class duplicates, find specific resource locations, etc.

Documentation available at http://jhades.github.io

Example of a classpath problem

Let's say a java web application works fine in development, but when deploying it to a server the following problem occurs:


java.lang.ClassCastException: org.apache.bval.jsr303.ApacheValidationProvider cannot be cast to javax.validation.spi.ValidationProvider
	javax.validation.Validation$DefaultValidationProviderResolver.getValidationProviders(Validation.java:332)
	javax.validation.Validation$GenericBootstrapImpl.configure(Validation.java:256)
	javax.validation.Validation.buildDefaultValidatorFactory(Validation.java:111)
	classloaders.test.TestServlet.doGet(TestServlet.java:33)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
	org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:91)

How to troubleshoot

JHades provides several commands that allow to extract from the runtime environment a lot of information which is important for understanding what is going on. Namelly these types of questions can be answered:

  • are there any overlapping jars, with different versions of the same class?
  • Are those multiple versions of the same class all identical or not ?
  • where are the different versions of a given class located ?
  • which class loader is loading which version of a given class ?
  • What does the chain of classloaders look like, how are the classloaders configured ?

This is an example of how to answer several of these questions for the sample problem above:

 
 new JHades()
	.printClassLoaders()
	.printClasspath()
	.overlappingJarsReport()
	.multipleClassVersionsReport()
	.findClassByName("org.apache.bval.jsr303.ApacheValidationProvider")
	.findClassByName("javax.validation.spi.ValidationProvider");

Jar overlap report

One of the most common sources of classpath problems are overlapping jar files, that contain multiple versions of the same class:


>>>> Jar overlap report: 
 
aspectjrt-1.7.2.jar overlaps with aspectjweaver-1.7.2.jar - total overlapping classes: 129
ejb3-persistence-1.0.2.GA.jar overlaps with hibernate-jpa-2.0-api-1.0.1.Final.jar - total overlapping classes: 91
stax-api-1.0-2.jar overlaps with xml-apis-1.4.01.jar - total overlapping classes: 34
javax.xml.soap-api-1.3.5.jar overlaps with saaj-api-1.3.jar - total overlapping classes: 29
commons-beanutils-1.8.3.jar overlaps with commons-collections-3.2.1.jar - total overlapping classes: 10
xbean-2.2.0.jar overlaps with xml-apis-1.4.01.jar - total overlapping classes: 6
commons-logging-1.1.1.jar overlaps with jcl-over-slf4j-1.6.6.jar - total overlapping classes: 6
 
Total number of classes with more than one version: 305

Check http://jhades.github.io for more details.

Versions

Version
1.0.4