Important Dates:
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Released in 1995/1996 by Sun Microsystems
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Oracle aquires Sun Microsystems in 2010
Overview:
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Java was created by Sun Microsystems as a safer coding language alternative for C/C++
- C/C++ can be prone to dangerous memory leaks
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Java, like C++, is object oriented
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Java applets
General Info:
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Statements can be grouped together with a method
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Program must have a method
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Must have a method called “main”
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Methods are enclosed in classes
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File name must match class
Executing Programs:
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Compiler vs Intepreter:
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Java is a complied language
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Compliers translate high-level code to low-level code and generates a new file
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faster
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needs to be complied for each machine
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compiled once
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Intepreter translates line by line and doesn’t create any new files
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slower
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runs on any machine
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intepreted every time is run
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Java Hybrid Approach:
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Java code can either be compiled or intepreted
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Java complies a bytecode and stores it into a .class file
- This bytecode can then be intepreted, which is similar to compile speed as bytecode is fairly low level
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Java code runs in the JVM (Java Virtual Machine)
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Code is run by Intepreter and not by cpu/hardware
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Allows code to be run on any device that has Java installed
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Commands needed to run a project:
- Javac Filename.java (Compile) Not mandatory for basic programs
- Java Filename (Intepret)