IIRC exec:java doesn't fork a new JVM so the java.class.path is the one from Maven itself. Your dependencies are "only" in a custom classloader. You might want to try exec:exec with java as the executable.
Le dim. 24 juil. 2022 à 20:46, Siddharth Jain <siddh...@gmail.com> a écrit : > we are running into the dreaded ClassNotFoundException in a project. Here > is the setup. Using JDK 11 and Maven 3.8.5. Trying to create sample test > project that uses memory-measurer > <https://github.com/DimitrisAndreou/memory-measurer> to measure memory. > First we mvn packaged and installed the memory-measurer artifact into M2 > repository. Then we created a test project in which we add dependency on > memory-measurer. The project compiles fine but gives error on running (we > run using mvn exec:java plugin): > > Caused by: java.lang.ClassNotFoundException: > com.google.common.base.Preconditions > at jdk.internal.loader.BuiltinClassLoader.loadClass > (BuiltinClassLoader.java:581) > at jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass > (ClassLoaders.java:178) > at java.lang.ClassLoader.loadClass (ClassLoader.java:521) > at objectexplorer.InstrumentationGrabber.checkSetup > (InstrumentationGrabber.java:20) > at objectexplorer.InstrumentationGrabber.instrumentation > (InstrumentationGrabber.java:25) > at objectexplorer.MemoryMeasurer.<clinit> (MemoryMeasurer.java:24) > at com.example.App.main (App.java:20) > at org.codehaus.mojo.exec.ExecJavaMojo$1.run (ExecJavaMojo.java:254) > at java.lang.Thread.run (Thread.java:834) > > > What have we tried? Here is output of mvn dependency:build-classpath: > > > /Users/xxx/.m2/repository/objectexplorer/memory-measurer/1.0-SNAPSHOT/memory-measurer-1.0-SNAPSHOT.jar:/Users/xxx/.m2/repository/com/google/code/findbugs/jsr305/3.0.2/jsr305-3.0.2.jar:/Users/xxx/.m2/repository/com/google/guava/guava/19.0/guava-19.0.jar:/Users/xxx/.m2/repository/junit/junit/4.11/junit-4.11.jar:/Users/xxx/.m2/repository/org/hamcrest/hamcrest-core/1.3/hamcrest-core-1.3.jar > > we unpacked guava-19.0.jar in a temp directory and can see > > -rw-r--r-- 1 xxx staff 5252 Aug 25 2014 > /Users/xxx/temp/com/google/common/base/Preconditions.class > > in it. The next thing we tried is printing > System.getProperty("java.class.path"). This gives: > > /Library/Downloads/apache-maven-3.8.5/boot/plexus-classworlds-2.6.0.jar > > above does not contain the classpath calculated by mvn dependency plugin. > Question 1: Why? > > Question 2: When we printed System.getProperty("java.class.path") in > another working project we got same result. It seems the classpath when > using mvn exec:java is always > > /Library/Downloads/apache-maven-3.8.5/boot/plexus-classworlds-2.6.0.jar > > How is the other project able to load classes from above classpath? Why is > mvn > exec:java not using correct classpath? How do we fix this? > > > Here <https://gist.github.com/siddjain/5d2afee15a756b689c5231488e6c29be> > is > output of maven with the -X switch. You can see following debug info: > > > [DEBUG] Adding project dependency artifact: memory-measurer to classpath > [DEBUG] Adding project dependency artifact: jsr305 to classpath > *[DEBUG] Adding project dependency artifact: guava to classpath* here > <https://gist.github.com/siddjain/2ceaca405acdaf460df94a064e07c17f> is > pom.xml. would be great if someone could help us out. >
