I am assuming you are using java 7, thus you get a compiler warning, when you don’t close the resource you should close your scanner usually in a finally block. Scanner scanner = null; try { scanner = new Scanner(System.in); //rest of the code } finally { if(scanner!=null) scanner.close(); } Or even better: use the … Read more
Yes you are right. Garbage collection frees Java heap (memory) but close() frees OS resources used for open file (number of open files is limited on most system) and assures that the data is really written. But many classes such as FileInputStream and RandomAccessFile are written with a finalize() method which ensures that IF an … Read more
Yes, this was a deliberate decision. We considered both alternatives. The operating design principle here is “whoever acquires the resource should release the resource”. Files don’t auto-close when you read to EOF; we expect files to be closed explicitly by whoever opened them. Streams that are backed by IO resources are the same. Fortunately, the … Read more