Sanel Zukan created BCEL-373:
--------------------------------
Summary: Add support for GraalVM
Key: BCEL-373
URL: https://issues.apache.org/jira/browse/BCEL-373
Project: Commons BCEL
Issue Type: Bug
Components: Main
Affects Versions: 6.10.0
Reporter: Sanel Zukan
I'm working on a small tool called "jarbloat" (written in Clojure but should
work on any JVM language that produces jar files) [1] for inspecting JAR files.
I'm using BCEL to analyze class dependencies and package names. Although I have
alternative code for computing package names based on paths, sadly, I don't
have any alternative for fetching class dependencies outside of BCEL.
Now, jarbloat works fine when compiled usual way (uberjar/fatjar), but when I
compile it with GraalVM, BCEL code will throw NullPointerException:
```
java.lang.ExceptionInInitializerError
at
org.apache.bcel.util.SyntheticRepository.getInstance(SyntheticRepository.java:38)
at org.apache.bcel.classfile.JavaClass.<init>(JavaClass.java:145)
at org.apache.bcel.classfile.ClassParser.parse(ClassParser.java:179)
at
jarbloat.class_analyzer.BCELAnalyzer.load_class(class_analyzer.clj:64)
at jarbloat.analyzer$analyze_entry_deps.invokeStatic(analyzer.clj:128)
at jarbloat.analyzer$analyze_entry_deps.invoke(analyzer.clj:118)
at jarbloat.analyzer$analyze_jar$fn__706.invoke(analyzer.clj:156)
at clojure.core$map$fn__4785.invoke(core.clj:2646)
at clojure.lang.LazySeq.sval(LazySeq.java:40)
at clojure.lang.LazySeq.seq(LazySeq.java:49)
at clojure.lang.RT.seq(RT.java:521)
at clojure.core$seq__4357.invokeStatic(core.clj:137)
at clojure.core$filter$fn__4812.invoke(core.clj:2700)
at clojure.lang.LazySeq.sval(LazySeq.java:40)
at clojure.lang.LazySeq.seq(LazySeq.java:56)
at clojure.lang.RT.seq(RT.java:521)
at clojure.core$seq__4357.invokeStatic(core.clj:137)
at jarbloat.printer$do_print_dot.invokeStatic(printer.clj:13)
at jarbloat.analyzer$analyze_jar.invokeStatic(analyzer.clj:160)
at jarbloat.core$handle_args.invokeStatic(core.clj:91)
at jarbloat.core$_main.invokeStatic(core.clj:105)
at jarbloat.core$_main.doInvoke(core.clj:99)
at clojure.lang.RestFn.applyTo(RestFn.java:137)
at jarbloat.core.main(Unknown Source)
Caused by: java.lang.NullPointerException
at [email protected]/java.util.Objects.requireNonNull(Objects.java:208)
at
[email protected]/sun.nio.fs.UnixFileSystem.getPath(UnixFileSystem.java:263)
at [email protected]/java.nio.file.Path.of(Path.java:147)
at [email protected]/java.nio.file.Paths.get(Paths.java:69)
at org.apache.bcel.util.ClassPath.getClassPath(ClassPath.java:481)
at org.apache.bcel.util.ClassPath.<clinit>(ClassPath.java:443)
```
This happens when I set GraalVM's native-image to use
`--initialize-at-run-time=org.apache.bcel.util.ClassPath` argument. Without it,
GraalVM will complain with the following error:
```
Error: Detected a ZipFile object in the image heap. A ZipFile object contains
pointers to unmanaged C memory and file descriptors, and these resources are no
longer available at image runtime. To see how this object got instantiated use
--trace-object-instantiation=java.util.zip.ZipFile. The object was probably
created by a class initializer and is reachable from a static field. You can
request class initialization at image runtime by using the option
--initialize-at-run-time=<class-name>. Or you can write your own initialization
methods and call them explicitly from your main entry point.
Trace: Object was reached by
reading field org.apache.bcel.util.ClassPath$AbstractZip.zipFile of constant
org.apache.bcel.util.ClassPath$Module@3956260a:
/opt/graalvm-jdk-17.0.12+8.1/jmods/java.se.jmod
indexing into array java.lang.Object[]@761be02f: [Ljava.lang.Object;@761be02f
reading field java.util.ArrayList.elementData of constant
java.util.ArrayList@3eb61e52: [[/modules/jdk.internal.vm.compiler,
/modules/com.oracle.graal.graal_enterprise,...
reading field org.apache.bcel.util.ClassPath.paths of constant
org.apache.bcel.util.ClassPath@2f5aa92f:
/opt/graalvm-jdk-17.0.12+8.1/lib/modules:/opt/graalvm-jdk-17.0.12+8.1/jmods/java...
scanning root org.apache.bcel.util.ClassPath@2f5aa92f:
/opt/graalvm-jdk-17.0.12+8.1/lib/modules:/opt/graalvm-jdk-17.0.12+8.1/jmods/java...
embedded in
org.apache.bcel.util.SyntheticRepository.getInstance(SyntheticRepository.java:38)
parsing method
org.apache.bcel.util.SyntheticRepository.getInstance(SyntheticRepository.java:38)
reachable via the parsing context
at static root method.(Unknown Source)
```
After some digging through the code, I found that BCEL has some variables
initialized when the class is initialized (e.g. [2], [3], and [4]). I'm getting
the impression that the problem starts in `ClassPath.getClassPath()` [5]. Some
values, like `SystemProperties.getJavaHome()`[6], will be null on GraalVM.
I'm not very familiar with BCEL internals, but after some rough checking
things, maybe making this [2] repository initialization lazy could solve and
allowing repository to be null, could solve the issue. Any thoughts?
Tested with these GraalVM native-image versions:
```
$ /opt/graalvm/bin/native-image --version
GraalVM 22.0.0.2 Java 17 CE (Java Version 17.0.2+8-jvmci-22.0-b05)
$ /opt/graalvm-jdk-17.0.12+8.1/bin/native-image --version
native-image 17.0.12 2024-07-16
GraalVM Runtime Environment Oracle GraalVM 17.0.12+8.1 (build
17.0.12+8-LTS-jvmci-23.0-b41)
Substrate VM Oracle GraalVM 17.0.12+8.1 (build 17.0.12+8-LTS, serial gc,
compressed references)
```
[1] https://github.com/sanel/jarbloat
[2]
https://github.com/apache/commons-bcel/blob/master/src/main/java/org/apache/bcel/classfile/JavaClass.java#L145
[3]
https://github.com/apache/commons-bcel/blob/master/src/main/java/org/apache/bcel/util/SyntheticRepository.java#L38
[4]
https://github.com/apache/commons-bcel/blob/master/src/main/java/org/apache/bcel/util/ClassPath.java#L443
[5]
https://github.com/apache/commons-bcel/blob/master/src/main/java/org/apache/bcel/util/ClassPath.java#L470
[6]
https://github.com/apache/commons-bcel/blob/master/src/main/java/org/apache/bcel/util/ClassPath.java#L481
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