Rune Flobakk
3 innlegg
Extend your super knowledge on Generics
We all know and appreciate Java Generics. It enables us to say "oh, this is a List of Strings", "oh, this is a Comparator for Integers", and the compiler will forbid you to add numbers to your list, or sorting your List of Strings by comparing Integers. Because it does not make sense. Before Generics was introduced in Java 5.0 in 2004, nothing was stopping you from expressing these nonsensical actions, and things would blow up when running your program, instead of being told already when writing the code that there is no way this will work.
We all know and appreciate Java Generics. It enables us to say "oh, this is a List of Strings", "oh, this is a Comparator for Integers", and the compiler will forbid you to add numbers to your list, or sorting your List of Strings by comparing Integers. Because it does not make sense. Before Generics was introduced in Java 5.0 in 2004, nothing was stopping you from expressing these nonsensical actions, and things would blow up when running your program, instead of being told already when writing the code that there is no way this will work.
Good ol’ I/O streams
No, not the Stream API introduced in Java 8, but the API for stream-based I/O which has been part of the JDK since Java 1.0. That is even older than the Collections Framework, which you had to wait until Java 1.2 to be available. And as with the Java Collections, even though the java.io API is quite dated, it is still heavily in use. InputStreams and OutputStreams are passed around, and consumed and written to, also in applications which are written nowadays.
No, not the Stream API introduced in Java 8, but the API for stream-based I/O which has been part of the JDK since Java 1.0. That is even older than the Collections Framework, which you had to wait until Java 1.2 to be available. And as with the Java Collections, even though the java.io API is quite dated, it is still heavily in use. InputStreams and OutputStreams are passed around, and consumed and written to, also in applications which are written nowadays.
Never use toString() for behaviour
Every object in Java has a toString() method which can be called to get a String-representation of any object at hand. If left unoverridden, it only yields a description of its class and hash code, and not really useful for much.
Every object in Java has a toString() method which can be called to get a String-representation of any object at hand. If left unoverridden, it only yields a description of its class and hash code, and not really useful for much.