Broken bytecode when iterating over String array via polymorphic data type

Issue #278 resolved
Jesper Öqvist created an issue

ExtendJ 8.1.0-27-gcd7effa Java SE 5

The following program is not executable when compiled with ExtendJ:

// Test using an enhanced-for loop to iterate elements of an
// array stored in a polymorphic container type.
// .result: EXEC_PASS
public class Test {
  public static void main(String[] args) {
        new Container<String[]>(
            new String[] { "x", " marks", " the spot" })));

  static String join(Container<String[]> values) {
    StringBuilder message = new StringBuilder();
    for (String part : values.get()) {
    return message.toString();


class Container<T> {
  private final T value;

  public Container(T value) {
    this.value = value;

  T get() {
    return value;

Expected result: the program should be runnable and give the output x marks the spot.

Actual result: the program fails to run with this error:

    [junit] [FAIL] runTest[run/generics/container_06](tests.extendj.TestJava7)
    [junit] Error output files differ expected:<[]> but was:<[Exception in thread "main" java.lang.IncompatibleClassChangeError: Class [Ljava.lang.String; does not implement the requested interface java.lang.Iterable

Comments (1)

  1. Jesper Öqvist reporter

    Fix enhanced-for code generation issue

    Array types could incorrectly be treated as non-array types due to type erasure handling in enhanced-for statement code generation.

    fixes #278 (bitbucket)

    → <<cset 8af0e3f022bb>>

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