j2objc error adding guava (When.o is missing)

Question

I'm playing with j2objc to see if I can use guava in my project.

My project is quite simple: A single view application configured for j2obcj (https://github.com/google/j2objc/wiki/Xcode-Build-Rules) with a custom line added to the appDelegete.m

#include "java/util/ArrayList.h"
#include "com/google/common/collect/Lists.h"
[...]
[ComGoogleCommonCollectLists newArrayList];

Trying to compile it generates the error:

Undefined symbols for architecture x86_64:
  "_JavaxAnnotationMetaWhenEnum_initialized", referenced from:
      +[ComGoogleCommonBaseCharMatcher __annotations_removeFromWithJavaLangCharSequence_] in libguava.a(CharMatcher.o)
      +[ComGoogleCommonBaseCharMatcher __annotations_retainFromWithJavaLangCharSequence_] in libguava.a(CharMatcher.o)
      +[ComGoogleCommonBaseCharMatcher __annotations_replaceFromWithJavaLangCharSequence_withChar_] in libguava.a(CharMatcher.o)
      +[ComGoogleCommonBaseCharMatcher __annotations_replaceFromWithJavaLangCharSequence_withJavaLangCharSequence_] in libguava.a(CharMatcher.o)
      +[ComGoogleCommonBaseCharMatcher __annotations_trimFromWithJavaLangCharSequence_] in libguava.a(CharMatcher.o)
      +[ComGoogleCommonBaseCharMatcher __annotations_trimLeadingFromWithJavaLangCharSequence_] in libguava.a(CharMatcher.o)
      +[ComGoogleCommonBaseCharMatcher __annotations_trimTrailingFromWithJavaLangCharSequence_] in libguava.a(CharMatcher.o)
      ...
  "_JavaxAnnotationMetaWhenEnum_values_", referenced from:
      +[ComGoogleCommonBaseCharMatcher __annotations_removeFromWithJavaLangCharSequence_] in libguava.a(CharMatcher.o)
      +[ComGoogleCommonBaseCharMatcher __annotations_retainFromWithJavaLangCharSequence_] in libguava.a(CharMatcher.o)
      +[ComGoogleCommonBaseCharMatcher __annotations_replaceFromWithJavaLangCharSequence_withChar_] in libguava.a(CharMatcher.o)
      +[ComGoogleCommonBaseCharMatcher __annotations_replaceFromWithJavaLangCharSequence_withJavaLangCharSequence_] in libguava.a(CharMatcher.o)
      +[ComGoogleCommonBaseCharMatcher __annotations_trimFromWithJavaLangCharSequence_] in libguava.a(CharMatcher.o)
      +[ComGoogleCommonBaseCharMatcher __annotations_trimLeadingFromWithJavaLangCharSequence_] in libguava.a(CharMatcher.o)
      +[ComGoogleCommonBaseCharMatcher __annotations_trimTrailingFromWithJavaLangCharSequence_] in libguava.a(CharMatcher.o)
      ...
  "_OBJC_CLASS_$_JavaxAnnotationCheckForNull", referenced from:
      objc-class-ref in libguava.a(Ints.o)
      objc-class-ref in libguava.a(AndroidInteger.o)
  "_OBJC_CLASS_$_JavaxAnnotationCheckReturnValue", referenced from:
      objc-class-ref in libguava.a(CharMatcher.o)
      objc-class-ref in libguava.a(Joiner.o)
      objc-class-ref in libguava.a(Splitter.o)
      objc-class-ref in libguava.a(CacheBuilder.o)
      objc-class-ref in libguava.a(BaseEncoding.o)
      objc-class-ref in libguava.a(UnsignedLong.o)
      objc-class-ref in libguava.a(UnsignedInteger.o)
      ...
  "_OBJC_CLASS_$_JavaxAnnotationMetaWhenEnum", referenced from:
      objc-class-ref in libguava.a(CharMatcher.o)
      objc-class-ref in libguava.a(Joiner.o)
      objc-class-ref in libguava.a(Splitter.o)
      objc-class-ref in libguava.a(CacheBuilder.o)
      objc-class-ref in libguava.a(BaseEncoding.o)
      objc-class-ref in libguava.a(UnsignedLong.o)
      objc-class-ref in libguava.a(UnsignedInteger.o)
      ...
  "_OBJC_CLASS_$_JavaxAnnotationNullable", referenced from:
      objc-class-ref in libguava.a(Equivalence.o)
      objc-class-ref in libguava.a(FunctionalEquivalence.o)
      objc-class-ref in libguava.a(Functions.o)
      objc-class-ref in libguava.a(Joiner.o)
      objc-class-ref in libguava.a(Objects.o)
      objc-class-ref in libguava.a(Optional.o)
      objc-class-ref in libguava.a(PairwiseEquivalence.o)
      ...
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation) 

It looks like there is a problem while linking, there is no When.o in libjre_emul.a.

I've tried running the following line without any issues, just to check that the javax package was there

#include "javax/xml/parsers/SAXParser.h"
[...]
[[JavaxXmlParsersSAXParser alloc] init];

Also checked that SAXParser.i is in libjre_emul

$ otool -o lib/libjre_emul.a  | grep .o\): | grep SAXParser
lib/libjre_emul.a(SAXParser.o):
lib/libjre_emul.a(SAXParserFactory.o):
lib/libjre_emul.a(SAXParserFactoryImpl.o):
lib/libjre_emul.a(SAXParserImpl.o):

But in the case of trying When

#include "javax/annotation/meta/When.h"
[...]
[JavaxAnnotationMetaWhenEnum values];

I got an error similar to the one with guava

Undefined symbols for architecture x86_64:
  "_OBJC_CLASS_$_JavaxAnnotationMetaWhenEnum", referenced from:
      objc-class-ref in AppDelegate.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

After checking libjre_emul there is no When.o

otool -o lib/libjre_emul.a  | grep .o\): | grep When

My settings are:

J2OBJC_HOME = ./bin/j2objc-0.9.5;
HEADER_SEARCH_PATHS = $(inherited) "${J2OBJC_HOME}/include";
LIBRARY_SEARCH_PATHS = $(inherited) "${J2OBJC_HOME}/lib";
OTHER_LDFLAGS = $(inherited) -l"z" -l"jre_emul" -l"guava" -l"icucore" -framework "Security" -ObjC;

I've tried different version (0.9.5, 0.9.4, 0.9.3, 0.9) but the error remains.

In conclusion, as far as I know there is no way of using guava with j2objc, because it depends on missing symbols.

Can anyone prove me wrong, hopefully? I really want to start using j2objc in a real project!

Thanks in advance! Merry Christmas!

Answer 1

Try linking in the jsr305 library (-ljsr305), as it defines the javax.annotation annotations referenced above.