浅谈两个jar包中包含完全相同的包名和类名的加载问题

<plugin>
    <artifactid>maven-assembly-plugin</artifactid>
    <version>2.4</version>
    <configuration>
     <descriptorrefs>
      <descriptorref>jar-with-dependencies</descriptorref>
     </descriptorrefs>
     <archive>
      <manifest>
       <mainclass>main.main</mainclass>
      </manifest>
     </archive>
    </configuration>
    <executions>
     <execution>
      <id>make-assembly</id>
      <phase>package</phase>
      <goals>
       <goal>single</goal>
      </goals>
     </execution>
    </executions>
   </plugin>
配置了一个manifest标签来配置main函数的入口。然后通过如下指令来实现打包。
 
mvn assembly:assembly

protected class<?> loadclass(string name, boolean resolve)
  throws classnotfoundexception
 {
  synchronized (getclassloadinglock(name)) {
   // first, check if the class has already been loaded
   class<?> c = findloadedclass(name);
   if (c == null) {
    long t0 = system.nanotime();
    try {
     if (parent != null) {
      c = parent.loadclass(name, false);
     } else {
      c = findbootstrapclassornull(name);
     }
    } catch (classnotfoundexception e) {
     // classnotfoundexception thrown if class not found
     // from the non-null parent class loader
    }
 
    if (c == null) {
     // if still not found, then invoke findclass in order
     // to find the class.
     long t1 = system.nanotime();
     c = findclass(name);
 
     // this is the defining class loader; record the stats
     sun.misc.perfcounter.getparentdelegationtime().addtime(t1 - t0);
     sun.misc.perfcounter.getfindclasstime().addelapsedtimefrom(t1);
     sun.misc.perfcounter.getfindclasses().increment();
    }
   }
   if (resolve) {
    resolveclass(c);
   }
   return c;
  }
 }