Some people think that it is simply a matter of what the words mean. I think there is more to it than that, but let us start with the words. In the general context: A specification is a document that specifies (or defines) something. A request is statement (written or verbal) asking for something. A … Read more
Note that the wording in the JLS of that particular section has changed significantly since then. It now (JLS 11) reads: 15.9.5. Anonymous Class Declarations: An anonymous class is never final (§8.1.1.2). The fact that an anonymous class is not final is relevant in casting, in particular the narrowing reference conversion allowed for the cast … Read more
Are there any guarantees about which classes are loadable by the bootstrap class loader in every JVM? The core bits and pieces of the language, plus supporting implementation classes. Not guaranteed to include any class that you write. (The normal JVM loads your classes in a separate classloader from the bootstrap one, and in fact … Read more
I think you found this bug in the compiler: JDK-8029718 (or this similar one in Eclipse: 434642). Compare to JLS §15.12.2.1. Identify Potentially Applicable Methods: … A lambda expression (§15.27) is potentially compatible with a functional interface type (§9.8) if all of the following are true: The arity of the target type’s function type is … Read more
Variables declared in Interface are implicitly public static final. This is what JLS 9.3 says : Every field declaration in the body of an interface is implicitly public, static, and final. It is permitted to redundantly specify any or all of these modifiers for such fields. Read through the JLS to get an idea why … Read more
The reason is explained in the Java Language Specification in an example in Section 15.11, quoted below: … The last line shows that, indeed, the field that is accessed does not depend on the run-time class of the referenced object; even if s holds a reference to an object of class T, the expression s.x … Read more
You can always cast to what you need, like this return (Class<List<String>>) new ArrayList<String>().getClass(); or return (Class<List<String>>) Collections.<String>emptyList().getClass(); But I assume that’s not what you are after. Well it works, with a warning, but it isn’t exactly “beautiful”. I just found this Why is there no class literal for wildcard parameterized types? Because a wildcard … Read more
Member variables cannot be overridden like methods. The number variables in your classes Beta and Gama are hiding (not overriding) the member variable number of the superclass. By casting you can access the hidden member in the superclass.
§15.11. Field Access Expressions: If the field is static: The Primary expression is evaluated, and the result is discarded. If evaluation of the Primary expression completes abruptly, the field access expression completes abruptly for the same reason. Where earlier it states that field access is identified by Primary.Identifier. This shows that even though it seems … Read more
From the Java Language Specification (on Expressions): 15.7.4 Argument Lists are Evaluated Left-to-Right In a method or constructor invocation or class instance creation expression, argument expressions may appear within the parentheses, separated by commas. Each argument expression appears to be fully evaluated before any part of any argument expression to its right.