Discussion 1

Compilation

Java is a compiled language. This means that we must compile the java source code into byte code that the computer (Java Virtual Machine) can read.

This is in contrast to some interpreted languages like python in which you run the program directly from the source file.¹

What are the benefits of compilation?

• Speed: compilation converts source code to machine-readable code which runs faster
• “Write Once, Run Everywhere”: Bytecode runs on the Java Virtual Machine so any computer with a JVM can run the files that you compiled on your machine

Declare + Initialize

All variables in Java must be declared and initialized before use.

1. Declaration: states variable’s type and name. A variable can only be declared once.
2. Initialize: assign value to a variable

Note that we can reassign a variable if we would like, but we can’t declare it more than once!

int i = 0;
i = 7;
int i = 5; // error: variable already defined

Can we ‘delete’ variables? How could we reduce the amount of memory an object takes when we no longer need it?

Git Demo

Come to discussion!

To better understand git and the difference between add, commit, push, pull, merge then read this 61b using git guide.

1. Don’t worry about this but technically when you run a python file, it first compiles it and then runs it for you. Still, python is called interpreted because you run programs directly from the source file. ↩