Github user StephanEwen commented on the pull request:
https://github.com/apache/incubator-flink/pull/85#issuecomment-50667122
I found a good way to detect lambdas. It only works if the SAM interface is
serializable, but ours are always.
The trick is to search for the `writeReplace` method from serializable
objects and see whether it returns a `SerializedLambda`.
```
public interface LambdaFunction extends java.io.Serializable {
String doComputation(Integer value);
}
public static void main(String[] args) throws Exception {
LambdaFunction func = (theInteger) -> "string " +
String.valueOf(theInteger);
for (Class<?> clazz = func.getClass(); clazz != null; clazz =
clazz.getSuperclass()) {
try {
Method replaceMethod = clazz.getDeclaredMethod("writeReplace");
replaceMethod.setAccessible(true);
Object serializedForm = replaceMethod.invoke(func);
if (serializedForm instanceof SerializedLambda) {
SerializedLambda sl = (SerializedLambda) serializedForm;
System.out.println(sl);
break;
}
}
catch (NoSuchMethodError e) {
// fall through the loop and try the next class
}
catch (Throwable t) {
t.printStackTrace();
return;
}
}
}
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