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Java Forum / General / September 2007java newbie question
Hello, I'm studying Java, and now trying to make sense of the concept of types. Would it be correct to say: a Java type is a classification of what could potentially be bound to a Java variable Also, The Java class Class really describes types. Would it have made more sense to call this class Type instead of Class? > Hello, > [quoted text clipped - 8 lines] > Also, The Java class Class really describes types. Would it have made > more sense to call this class Type instead of Class? <http://java.sun.com/docs/books/jls/third_edition/html/typesValues.html> > a Java type is a classification of what could potentially be bound > to a Java variable This works for me. I also think of type as how the JVM will interpret any given bit pattern to which the variable is bound. > Also, The Java class Class really describes types. Would it have made > more sense to call this class Type instead of Class? Hmm, but ints, chars, booleans and all the other primitives are also types, but I don't think that Class describes them. Class only deals with Java objects (most of the language, admittedly) but there are a few types it doesn't abstract. Also, generics are a type, but their type gets erased during compilations. I don't think Class can represent the un-erased type. >> a Java type is a classification of what could potentially be bound >> to a Java variable [quoted text clipped - 9 lines] > with Java objects (most of the language, admittedly) but there are a few > types it doesn't abstract. Each of the wrapper types has a public static final TYPE field that references the Class object for the corresponding primitive. For example: "public static final Class<Integer> TYPE The Class instance representing the primitive type int." in class Integer. Class objects for primitives are important in some reflection interfaces. > Also, generics are a type, but their type gets erased during > compilations. I don't think Class can represent the un-erased type. I'm not sure generics count as a type, or anything else, in a running program. They are effectively a form of compile-time assertion that enables some extra checking. Patricia > > Also, The Java class Class really describes types. Would it have made > > more sense to call this class Type instead of Class? [quoted text clipped - 3 lines] > with Java objects (most of the language, admittedly) but there are a few > types it doesn't abstract. Although primitive types aren't objects, they can return a Class object. Example: Class cl = int.class; // int.class is an object of type Class >> > Also, The Java class Class really describes types. Would it have made >> > more sense to call this class Type instead of Class? [quoted text clipped - 8 lines] > > Class cl = int.class; // int.class is an object of type Class <http://java.sun.com/docs/books/jvms/second_edition/html/Concepts.doc.html#23409> dave wrote: >>>> Also, The Java class Class really describes types. Would it have made >>>> more sense to call this class Type instead of Class? ... >> Although primitive types aren't objects, they can return a Class >> object. Example: >> >> Class cl = int.class; // int.class is an object of type Class Interfaces are also types, but not classes. Class != type. Interface != type. Primitive != type. Why are you interested in redefining the Java language? Is "class" such a bad word?  SignatureLew > Interfaces are also types, but not classes. > > Class != type. Interface != type. Primitive != type. > > Why are you interested in redefining the Java language? Is "class" such a bad > word? I'm not, I just asked if it made sense, it seemed logical to me, although I admit I'm not a Java expert. In fact, you'll notice from the title post I consider myself a Java "newbie", meaning there is no way in hell I would think I'm smarter than the people at Sun who write the Java specification! My hope was to understand a bit more on exactly what types means in Java. Anyway, thanks especially Jeff Higgins for those links. Those pretty much clear up the issues for me at least. I'm a newb2 and have had a lot of help from the good people who frequent this group. I'm happy this "blind pig" was able to help find an acorn. JH >>> Also, The Java class Class really describes types. Would it have made >>> more sense to call this class Type instead of Class? [quoted text clipped - 7 lines] > > Class cl = int.class; // int.class is an object of type Class Well that's darn interesting. That's for pointing that out! >Also, The Java class Class really describes types. Would it have made >more sense to call this class Type instead of Class? Classes apply only to Objects. Type would be Objects plus primitives. Class has some kludges to describe primitives, but for the most part it applies only to classes. So I think either the name Class or Type would have been appropriate. SignatureRoedy Green Canadian Mind Products The Java Glossary http://mindprod.com Free MagazinesGet these publications absolutely FREE for up to 12 months. There are no hidden fees and no obligation. Simply choose a title, complete the application form and submit it. Read more ...
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