Headfirst Java: Chapter 4

Classes: What are they? What do they do?

• Classes are structures of code that can tell what exactly an object knows and or does
• Things, or data that an object knows are refered to as "Instance Variables"
• "Methods" are the things a specific object does
• Methods use Instance Variables explicitly to differentiate between various objects.
• Methods can have parameters like functions in Python. 
• Methods in Java can have several parameters.
• When using parameters they must match the variable type IN the method. (ex. If i use a float for a parameter and call it an int inside of the method, it wont compile)
• Methods must return somthing unless it is explicity stated it wont with a  "void" command.

Activities:

- The first activity was relatively easy to decipher, side A being correctly coded, will output 42 84. Section B was moderately dificult however. The only error i spotted in the code was "void getTime()". The only reason this was flawed because it wasnt declaired as a string variable, so Java would not be able to read it correctly. It also seemed worth to note that GET methods must return a value of some sort.

- This section was hard for me to keep track of becasue the modification of many variables in quick sucession. I ended up sorting through it one line at a time plugging in each of the values to figure out Java's output for all of the commands.