java.lang.NoSuchMethodError: java.nio.ByteBuffer.flip()Ljava/nio/ByteBuffer;

[pfirmstone]

Covariant return breaks runtime compatibility with Java 8.

Adding casts to source code fixes this issue.

[pfirmstone]

java.lang.NoSuchMethodError: java.nio.ByteBuffer.position(I)Ljava/nio/ByteBuffer;

[pfirmstone]

According to Felix:

apache/felix#114

Java 9 introduces overridden methods with covariant return types for the following methods in java.nio.ByteBuffer:

position​(int newPosition)
limit​(int newLimit)
flip​()
clear​()
mark​()
reset​()
rewind​()

In Java 9 they all now return ByteBuffer, whereas the methods they override return Buffer,
resulting in exceptions like this when executing on Java 8 and lower:
java.lang.NoSuchMethodError: java.nio.ByteBuffer.limit(I)Ljava/nio/ByteBuffer
This is because the generated byte code includes the static return type of the method, which is not found on Java 8 and lower because the overloaded methods with covariant return types don't exist (the issue appears even with source and target 8 or lower in compilation parameters).
The solution is to cast ByteBuffer instances to Buffer before calling the method.

[pfirmstone]

Also two abstract methods were added to Buffer in Java 9:

slice()
duplicate()

Which return Buffer, and are also implemented by ByteBuffer in previous versions of Java, but return ByteBuffer.

The solution in this case is to cast to ByteBuffer before calling these two methods.

[pfirmstone]

Refer to Issue #141

Array types need to remain as ByteBuffer [] for compatibility reasons, as array types cannot be cast to supertypes, eg ByteBuffer [] cannot be cast to Buffer [], casts can be performed outside of arrays. #141 was created by the changes made here.

[pfirmstone]

It turns out that this is a suboptimal solution to this problem, the OpenJDK team created a new complier flag for later Java platforms, to generate Java 8 compatible bytecodes. We should use the release compiler flag, instead of the source target flags.

<properties> <maven.compiler.release>8</maven.compiler.release> </properties>