FULL PRODUCT VERSION :
java version "1.5.0_06"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_06-112)
Java HotSpot(TM) Client VM (build 1.5.0_06-64, mixed mode, sharing)

ADDITIONAL OS VERSION INFORMATION :
Darwin Kernel Version 8.6.0: Tue Mar 7 16:58:48 PST 2006; root:xnu-792.6.70.obj~1/RELEASE_PPC Power Macintosh powerpc

EXTRA RELEVANT SYSTEM CONFIGURATION :
MacOS X 10.4.6

A DESCRIPTION OF THE PROBLEM :
Executing

find . -name "*.java" | xargs javadoc -use

in a directory containing a directory hierarchy of .java files produces the following output:

java.lang.NullPointerException
        at com.sun.tools.doclets.formats.html.PackageUseWriter.generatePackageUse(PackageUseWriter.java:180)
        at com.sun.tools.doclets.formats.html.PackageUseWriter.generatePackageList(PackageUseWriter.java:124)
        at com.sun.tools.doclets.formats.html.PackageUseWriter.generatePackageUse(PackageUseWriter.java:110)
        at com.sun.tools.doclets.formats.html.PackageUseWriter.generatePackageUseFile(PackageUseWriter.java:99)
        at com.sun.tools.doclets.formats.html.PackageUseWriter.generate(PackageUseWriter.java:78)
        at com.sun.tools.doclets.formats.html.ClassUseWriter.generate(ClassUseWriter.java:116)
        at com.sun.tools.doclets.formats.html.HtmlDoclet.generateOtherFiles(HtmlDoclet.java:92)
        at com.sun.tools.doclets.internal.toolkit.AbstractDoclet.startGeneration(AbstractDoclet.java:122)
        at com.sun.tools.doclets.internal.toolkit.AbstractDoclet.start(AbstractDoclet.java:64)
        at com.sun.tools.doclets.formats.html.HtmlDoclet.start(HtmlDoclet.java:42)
        at com.sun.tools.doclets.standard.Standard.start(Standard.java:23)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:585)
        at com.sun.tools.javadoc.DocletInvoker.invoke(DocletInvoker.java:269)
        at com.sun.tools.javadoc.DocletInvoker.start(DocletInvoker.java:143)
        at com.sun.tools.javadoc.Start.parseAndExecute(Start.java:340)
        at com.sun.tools.javadoc.Start.begin(Start.java:128)
        at com.sun.tools.javadoc.Main.execute(Main.java:41)
        at com.sun.tools.javadoc.Main.main(Main.java:31)

Executing the same command without the "-use" option proceeds normally to the end and creates all javadoc files as expected.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1) Create a directory hierarchy of java source files.
2) In the directory enclosing the hierarchy above, execute the command

find . -name "*.java" | xargs javadoc -use

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
I expected to see a complete set of generated javadoc html files for the classes in the directory hierarchy I specified.
ACTUAL -
Only a subset of the javadoc html files was generated, and the process stopped when the exception was thrown.

ERROR MESSAGES/STACK TRACES THAT OCCUR :
java.lang.NullPointerException
        at com.sun.tools.doclets.formats.html.PackageUseWriter.generatePackageUse(PackageUseWriter.java:180)
        at com.sun.tools.doclets.formats.html.PackageUseWriter.generatePackageList(PackageUseWriter.java:124)
        at com.sun.tools.doclets.formats.html.PackageUseWriter.generatePackageUse(PackageUseWriter.java:110)
        at com.sun.tools.doclets.formats.html.PackageUseWriter.generatePackageUseFile(PackageUseWriter.java:99)
        at com.sun.tools.doclets.formats.html.PackageUseWriter.generate(PackageUseWriter.java:78)
        at com.sun.tools.doclets.formats.html.ClassUseWriter.generate(ClassUseWriter.java:116)
        at com.sun.tools.doclets.formats.html.HtmlDoclet.generateOtherFiles(HtmlDoclet.java:92)
        at com.sun.tools.doclets.internal.toolkit.AbstractDoclet.startGeneration(AbstractDoclet.java:122)
        at com.sun.tools.doclets.internal.toolkit.AbstractDoclet.start(AbstractDoclet.java:64)
        at com.sun.tools.doclets.formats.html.HtmlDoclet.start(HtmlDoclet.java:42)
        at com.sun.tools.doclets.standard.Standard.start(Standard.java:23)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:585)
        at com.sun.tools.javadoc.DocletInvoker.invoke(DocletInvoker.java:269)
        at com.sun.tools.javadoc.DocletInvoker.start(DocletInvoker.java:143)
        at com.sun.tools.javadoc.Start.parseAndExecute(Start.java:340)
        at com.sun.tools.javadoc.Start.begin(Start.java:128)
        at com.sun.tools.javadoc.Main.execute(Main.java:41)
        at com.sun.tools.javadoc.Main.main(Main.java:31)

REPRODUCIBILITY :
This bug can be reproduced always.

CUSTOMER SUBMITTED WORKAROUND :
Not using the "-use" option works.