# ClassLoader question

Andrew Wright (wright@intertrust.com)
Thu, 03 Dec 98 14:44:00 P

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I'm trying to understand the reason why ClassLoader and
SecureClassLoader (in jdk1.2) delegate to the parent class
loader *before* checking the local name space. "Java Security"
by Oaks on p. 35 gives a brief explanation that I don't get.
Paraphrasing:
when the class loader that loaded class C from url U is asked to
provide java.lang.String, it must provide the expected version and
not some some version from url U.
Why does this matter? If C gets the version of java.lang.String from
its own url rather than the system version, thats C's own problem.
It shouldn't bother any classes not loaded from U, as these still
get the system version of java.lang.String.

Put another way, for class loaders to nest in a way that mimics
static (aka lexical) scoping, a class loader would first resolve
references within its own name space, and only try the parent
when it is unable to resolve the reference locally. Why don't
class loaders work this way?

Andrew Wright, InterTrust

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