java noSuchMethodError causes and solutions

java noSuchMethodError causes and solutions

Appearance reasons

A.class call B.methodX.

Run time loaded into the case of class B may be present in methodX

• methodX approach does not exist

• methodX A.class method signature and call B.methodX signatures do not match

root cause

Compile-time version B of inconsistencies and run-time version B

Run B in a jar with a plurality of classPath, loaded into the JVM error jar package

Different classLoader loaded to a different version B class.

ClassLoader child at the time when the parent class loader delegation, access to the B.class loaded into the parent classLoder

classification

jvm in class

• the reason

• Usually write code, compile time and jdk version used is relatively high, but time is running low jdk version used

• solution

• Confirm operating environment jdk version is correct

The company projects included in the category jar

• the reason

• The introduction of low version of the jar package

• The introduction of the snapshot is not the latest version of the package

• solution

• Modified version of the jar package is dependent on the correct version

• snapshot version of the package does not

• Add -U parameter when executing mvn command. mvn clean package / install -U

• not recommend

• Other environmental compile time, too, to add parameters

• Configuring maven

• https://blog.csdn.net/wangjun5159/article/details/49095881

• configured in settings.xml

nexus

central

http://central

true

true

always

• Not recommended for use

• Other people should also be amended

• Pom.xml in the project configuration

• Recommended

Projects rely on third parties jar included in the category

• the reason

• The introduction of low version of the jar package

• The introduction of more jar package, but is loaded into the wrong version of the jar package

• Subclass classLoader load the class time, delegate to the parent class loader classLoader low version of classLoader

• Targeting

• 1. Begin by -verbose: class find loads to which class

• 2. jvm class loader structure judgment, is that the class loader loads the class and then to find ways to solve

• solution

• Change to the correct version of the jar package

• Choosing the right package through maven jar command

• The first step: List dependent jar package

• mvn dependency: list command lists all current dependent (including direct and transfer) list, and ranges.

• mvn dependency: tree command lists all hierarchical dependence, dependence relationships can be seen from the book delivery.

• Step Two: using exclude exclude undesirable dependence

• Jvm using the View command to load the jar package which leads to errors

• -verbose:class