Cheat Sheet

This cheat sheet contains important takeaways that lead up to section two.

1. Getting Started

• class: contains all of your code.

• main(): entry point of your app.

• javac <file-name>.java: compiles your code.

• java <file-name>: runs the compiled code.

2. Variables

Data types

There are 6 main data types (we didn't cover boolean yet).

long can store very big numbers. But, int is faster and takes less memory.

Operators

Scanner

nextLine(): scans for a String value.

nextDouble(): scans for a double value.

nextLong(): scans for a long value.

nextInt(): scans for an int value.

Coding Pitfalls

Pitfall

---

Put math operations in brackets if you wish to embed them inside a String.

• Example: "5 + 2 is " + (5 + 2);

Pitfall

---

nextLine() Trap
Pitfall	nextLine() gets skipped when placed after nextInt() , nextDouble(), or nextLong().
Solution	Add a throwaway nextLine() before the "real" nextLine().
Explanation	The upcoming lesson on Delimiters will explain why this happens.

Good coding habits

• class: CamelCase.

• variable: lowerCamelCase.

Tips and tricks

Terminal

• Use the up key to run previous terminal commands.

• Write clear to clear the terminal output.

• Press the tab key for auto-complete.

Escape characters

• \n adds a new line of space.

• \t adds a new tab of space.

Shortcut keys

• Use CMD/Ctrl+/ to comment a highlighted piece of code.

---

Associated Course: The Complete Java Development Bootcamp

Related Course: The Complete Spring Boot Development Bootcamp – Become a Java Web Developer