Java Basics

Question 1

Java is similar with what language ?

Answer 1

1. C++
2. C#

Question 2

The advantages of Java

Answer 2

1. Platform Independence
   
   • Uses JVM
   • Uses bytecode to run on every devices
2. Java API
   
   • Stands for Application Programming Interface
   • Functions that are commonly used

Question 3

The interpretation of Java

Answer 3

1. Code ( public class )
2. javac ( compiled )
3. bytecode ( generate )
4. JVM ( execute )

Question 4

What does the Java API do ?

Answer 4

1. Do trigonometry
2. Write data to files
3. Retrieve information from database

Question 5

Features on Java

Answer 5

1. Type Checking
   
   • Must use the data types ( String , int , float )
2. Exception Handling
   
   • An unique approach to error handling
   • Handle by the JRE
3. Java Version Insanity
   
   • Updates bring in many improvement

Question 6

Java Name

Answer 6

1. JDK ( Java Development Kit )
2. SDK ( Software Development Kit )
3. JRE ( Java Runtime Environment )
4. JVM ( Java Virtual Machine )
5. Java SE ( Java Standard Edition )
6. Java EE ( Java Enterprise Edition )

Question 7

Where to install the newest version of Java ?

Answer 7

https://www.oracle.com/java/technologies/

Question 8

How to compile a file ?

Answer 8

1. Windows + R ( Type cmd )
2. Type drive name ( C: , D: )
3. Locate the folder using cd + Folder Name
4. Type javac name.java
5. Type java name

Question 9

How to compile more than a file ?

Answer 9

1. It it was in the same file , it will automatically compile it .
2. Use cmd , then type in all the file
   
   • javac Trial.java Trial1.java
3. Compile all file in the same folder
   
   • javac *.java

Question 10

Useful options in cmd

Answer 10

1. -classpath / -cp
   
   • Program uses class file in other folder
2. -deprecation
   
   • Let compiler warn us that we are using older Java API
3. -source
   
   • Limit the compiler to previous version of Java
4. -help
   
   • List the options that are available for javac command

Question 11

What are the uses of javap ?

Answer 11

1. Tell us what is inside the class files