LEARNING JAVA v19-03-04 Update

LEARNING JAVA
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Image source: Willi Glenz - Screenshot Eclipse

JAVA-BASICS

• Learning Java - tutorialspoint • javatpoint
• Learning Swing - tutorialspoint
• Bradley Kjell - Introduction to Computer Science using Java
• IdeOne - Online Compiler and IDE
• O'Reilly - AWT Reference

ORACLE-JAVA-TUTORIALS

• Getting Started
• Language Basics
• Object-Oriented Programming Concepts
• Classes and Objects
• Interfaces and Inheritance
• Numbers and Strings
• Packages
• Exceptions
• Basic I/O
• Concurrency
• Generics
• Annotations

TERMINAL

# apt-get install default-jdk default-jdk-doc openjdk-11-jdk openjdk-11-doc
$ java -version; javac -version
# update-java-alternatives -l
# update-java-alternatives -s java-1.11.0-openjdk-amd64
# update-alternatives --display java
# update-alternatives --config java
$ mkdir -p /tmp/java/{tools,test,phoenix};cd /tmp/java; ls -lisa
$ vim Main.java ^z fg
$ ( cd /tmp/java/; vim Main.java )

PRIMITIVE DATA TYPES

Type	Size	Range	Default	Class & Field
byte	8 bit	-2^7 to 2^7 -1	0
short	16 bit	-2^15 to 2^15 -1	0
int	32-bit	-2^31 to 2^31 -1	0	Integer.MIN_VALUE to Integer.MAX_VALUE
long	64 bit	-2^63 to 2^63-1	0L
float	32 bit	-3.4E38 to 3.4E38	0f
double	64 bit	-1.7E308 to 1.7E308	0d
char	16 bit	'\u0000' to '\uffff' (0 to 65,565)	'\u0000'
boolean	1 bit		false

OPERATORS

Arithmetic      + - * / & ++ --
Relational      == != > < >= <=
Bitwise         & | ^ ~ << >> >>>
Logical         && || !
Assignment      = += -= *= /= %= <<= >>=  &= ^= |=
Miscellaneous   ?: instanceof

MODIFIER

                Class Package Subclass World
private            ok       -        -     -
default            ok      ok        -     -
protected          ok      ok       ok     -
public             ok      ok       ok    ok