Java – Why is the folder name “bin” used in some frameworks and languages

Your observations are correct. C++ is a complicated beast, and the new keyword was used to distinguish between something that needed delete later and something that would be automatically reclaimed. In Java and C#, they dropped the delete keyword because the garbage collector would take care of it for you.

The problem then is why did they keep the new keyword? Without talking to the people who wrote the language it's kind of difficult to answer. My best guesses are listed below:

• It was semantically correct. If you were familiar with C++, you knew that the new keyword creates an object on the heap. So, why change expected behavior?
• It calls attention to the fact that you are instantiating an object rather than calling a method. With Microsoft code style recommendations, method names start with capital letters so there can be confusion.

Ruby is somewhere in between Python and Java/C# in it's use of new. Basically you instantiate an object like this:

f = Foo.new()

It's not a keyword, it's a static method for the class. What that means is that if you want a singleton, you can override the default implementation of new() to return the same instance every time. It's not necessarily recommended, but it's possible.

I think the main reason is that BlueJ runs your code in a VM with a debugger attached. BlueJ actually has two VMs running: the main one, and the one with your code inside (the user VM, aka the debug VM). The main VM has a debugger attached to the user VM, which allows it to do things like pause user code, inspect the state of objects and all sorts. I imagine this probably adds a fair bit of overhead (perhaps inhibiting the JIT compilation?); the speed that code executes is not a major concern for a learning environment like BlueJ, as long as it's reasonable.