可以JNI提出，要兑现在classpath中通配符扩展？ [英] Can JNI be made to honour wildcard expansion in the classpath?

问题描述

我有一个C二进制文件通过JNI调用了去渣。我设置CLASSPATH以somedir / *拿起所有的罐子在somedir。

I have a C binary that calls out to Java via JNI. I set CLASSPATH to somedir/* to pick up all the jars in somedir.

当我运行的二进制，所需的类定义不能被发现。当我运行

When I run the binary, a required class definition cannot be found. When I run

java that.class's.name 

从相同的命令行，类被成功找到。如果我明确地添加所有的罐子在somedir /到classpath中，一切都很正常，但导致的非常的类路径很长，我想这避免。

from the same command line, the class is successfully found. If I explicitly add all the jars in somedir/ to the classpath, everything works great, but that leads to a very long classpath which I'd like to avoid.

通过是否在classpath的JNI荣誉通配符扩展执行的JVM？是否可以做这样的？

Does a JVM executed via JNI honour wildcard expansion of the classpath? Can it be made to do so?

推荐答案

我通过阅读热点源$ C ​​$ C想出答案。

I figured out the answer by reading the hotspot source code.

只能通过两种 CLASSPATH 或 -cp / -classpath 受通配符扩展。然后这些作为一个系统属性来运行的JVM通过 -Djava.class.path 过去了。

Only paths passed via either CLASSPATH or -cp / -classpath are subject to wildcard expansion. These are then passed as a system property to the running JVM via -Djava.class.path.

您告诉JNI调用的JVM关于通过 JVMOptions 结构的类路径中，其中可能包括 -Djava.class.path ，但 -classpath 不会的不一定的荣幸（并在实践中，是不是热点实现）。由于 java.class.path 直接传递给JVM的系统属性，它不会通配符扩展，因此通配符将不起作用。

You tell a JNI-invoked JVM about a classpath via a JVMOptions structure, which may include -Djava.class.path but -classpath will not necessarily be honoured (and in practice, isn't by the hotspot implementation). Since java.class.path is directly passed to the JVM as a system property, it doesn't get wildcard expanded and therefore wildcards won't work.

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