javac (LTS-Versions 11-21) produces incorrect binar-code when using cascading lamdas

[r-pf]

Please provide a brief summary of the bug

When compiling the source code LamdaWithVarArgsCompilerProblem.java below with javac of one of the versions 21.0.3+9, 17.0.11+9 or 11.0.23+9 (or may be any version of these LTS-Major-Versions 11 - 21) the produced clas-file brings a ClassCastException when executing via java.
When compiled with Java 8 e.g. 1.8.0_412-b08 it works well.

Did you test with the latest update version?

• Yes

Please provide steps to reproduce where possible

Compile the source code below with javac of one of the JDK-Versions 21.0.3+9, 17.0.11+9 or 11.0.23+9 (or may be any version of these LTS-Major-Versions 11 - 21) :

javac LamdaWithVarArgsCompilerProblem.java

Then execute the compiled class-file via java.

LamdaWithVarArgsCompilerProblem.java :

import java.util.function.Consumer;
import java.util.function.Function;

public class LamdaWithVarArgsCompilerProblem {

  @SafeVarargs
  public final <P, T extends Throwable> void exec(
    final Consumer<P[]>  fi,
    final P ...         params
  )throws T
  {
    fi.accept(params);
  }

  @SafeVarargs
  public final <P, R, T extends Throwable> R execute(
    Function<P [], R>  fi1O,
    P ...             params
  )throws T
  {
    R result;
    
    result = fi1O.apply(params);
    System.out.println(params.getClass() + " - " + result);
    
    return result;
  }

  public static void main(
    String [] args
  )
  {
    LamdaWithVarArgsCompilerProblem lamdaWithVarArgsCompilerProblem;
    Function<Integer [], Integer>   function;
    
    lamdaWithVarArgsCompilerProblem = new LamdaWithVarArgsCompilerProblem();
    
    function = (a) -> Integer.valueOf(1);
    
          // This will work - `execute` isn't part of a lambda-expression
    lamdaWithVarArgsCompilerProblem.execute(function);
    
          // This will work - passed Integer-array to lamdaWithVarArgsCompilerProblem.execute(..)
    lamdaWithVarArgsCompilerProblem.exec( 
                      (a) -> lamdaWithVarArgsCompilerProblem.execute(function, new Integer [0]));
    
          // This will fail at runtime when compiled with Java11, Java17 or Java21
          // An Object [] will be passed to execute(..) instead of an expected Integer []
    lamdaWithVarArgsCompilerProblem.exec( 
                      (a) -> lamdaWithVarArgsCompilerProblem.execute(function));
    
  }
}

Expected Results

Compiled with 1.8.0_412-b08 => o.k.

user> java -cp . LamdaWithVarArgsCompilerProblem
class [Ljava.lang.Integer; - 1
class [Ljava.lang.Integer; - 1
class [Ljava.lang.Integer; - 1
user> 

Actual Results

Compiled with 21.0.3+9, 17.0.11+9 or 11.0.23+9 => not o.k.

user> java -cp . LamdaWithVarArgsCompilerProblem
class [Ljava.lang.Integer; - 1
class [Ljava.lang.Integer; - 1
Exception in thread "main" java.lang.ClassCastException: class [Ljava.lang.Object; cannot be cast to class [Ljava.lang.Integer; ([Ljava.lang.Object; and [Ljava.lang.Integer; are in module java.base of loader 'bootstrap')
	at LamdaWithVarArgsCompilerProblem.execute(LamdaWithVarArgsCompilerProblem.java:24)
	at LamdaWithVarArgsCompilerProblem.lambda$main$2(LamdaWithVarArgsCompilerProblem.java:51)
	at LamdaWithVarArgsCompilerProblem.exec(LamdaWithVarArgsCompilerProblem.java:12)
	at LamdaWithVarArgsCompilerProblem.main(LamdaWithVarArgsCompilerProblem.java:50)
user> 

An unexpected Object-array is passed. An Integer-array is expected.

What Java Version are you using?

21.0.3+9-LTS, 17.0.11+9 and 11.0.23+9

What is your operating system and platform?

ArchLinux, Windows 10

How did you install Java?

tar xvzf '../OpenJDK21U-jdk_x64_linux_hotspot_21.0.3_9.tar.gz'

tar xvzf '../OpenJDK17U-jdk_x64_linux_hotspot_17.0.11_9.tar.gz'

tar xvzf '../OpenJDK11U-jdk_x64_linux_hotspot_11.0.23_9.tar.gz'

Did it work before?

Yes.

Compiled with 1.8.0_412-b08 => o.k. (see "Expected Results" above)

There is a workaround:
The last (real) code-line is

(a) -> lamdaWithVarArgsCompilerProblem.execute(function));

Replacing this line with

(a) -> {lamdaWithVarArgsCompilerProblem.execute(function);});

is a workaround for this problem.

### Did you test with other Java versions?

```Shell
Compiled with 1.8.0_412-b08 => o.k. (see "Expected Results" above)
Compiled with 21.0.3+9, 17.0.11+9 or 11.0.23+9  => not o.k. (see "Actual Results" above)

Relevant log output

See "Expected Results" and "Actual Results" above.

[github-actions]

We are marking this issue as stale because it has not been updated for a while. This is just a way to keep the support issues queue manageable.
It will be closed soon unless the stale label is removed by a committer, or a new comment is made.

[karianna]

@r-pf So sorry for missing the original report. Does the issue still exist with the latest versions of 11, 17, 21?

[github-actions]

We are marking this issue as stale because it has not been updated for a while. This is just a way to keep the support issues queue manageable.
It will be closed soon unless the stale label is removed by a committer, or a new comment is made.

[r-pf]

@maintainer_karianna @karianna The problem isn't solved - please reopen this issue.
It occurs also with newest 11.0.25+9, 17.0.13+11 and 21.0.5+11 on Linux (on Windows I haven't tested yet again)