1. Installing Java on a Home machine For Windows Users: Download/Install: Go to http://www.oracle.com/technetwork/java/javase/downloads/jdk8- downloads-2133151.html http://www.oracle.com/technetwork/java/javase/downloads/jdk8- downloads-2133151.html Accept License Agreement and then download the file named “jdk-8u65- windows-i586.exe”. Save the file to the desktop and run it. The installer will install Java to: C:\Program Files\Java\jdk1.8.0_65\ Once the installer is finished, you must set your computer's path before Java will work correctly.

2. Installing Java on a Home machine (cont’d) Setting the Path: Go to the Control Panel and double-click System Select the Advanced tab Click on the Environment Variables button Look under System Variables for "Path" Click on "Path" and then click edit Add the following to the end of the Path ; C:\Program Files\Java\jdk1.8.0_65\bin Click OK. Click the "New" button. For the variable name, type: CLASSPATH For the value, type:.; NOTE: The above value in words is period semicolon; it is not a misprint. Click OK. Exit out of all the open windows

3. Installing Java on a Home machine (cont’d) To test if java is installed correctly: Open up a command prompt To do this click on Start and then Run Type in cmd.exe and click Ok Type java and hit enter If you see something like "command not found", then java is not installed correctly Otherwise you should see a list of options for running java

4. Developing a programming skill Learning to program a computer Training yourself to solve problems in a very detailed and organized manner You are already experienced in Intuitive problem solving Need to develop programming skill Write a problem solution IN terms of actions appropriate for a computer

5. Computer organization Computer system Hardware physical, tangible pieces such as chips, wires, and so on Useless without instructions to tell them what to do Driven by a series of instructions, in other words programs Software Programs and the data those programs use Intangible counterpart to the physical hardware components

6. Computer hardware Most computer have four major hardware parts Central Processing Unit (CPU): brain of the computer executes individual commands of a program Input/output devices allow human beings to interact with a computer Memory stores programs and data while being processed by CPU

7. Computer hardware (cont’d) Memory Input devicesOutput devices CPU

8. What is programming Computers performs tasks more efficiently, quickly, and accurately than we could by hand However, to be useful it must be programmed Computer programming: Devise a set of instructions to be executed by a computer In order to solve a given real world problem

9. How do we write a program? It is a two phase process Analysis and specification General solution (Algorithm ) Verify Problem-Solving Phase Concrete solution (Program ) Test Implementation Phase Maintenance Phase

10. Algorithm implementation Algorithm JAVA code C++ code Ada code Algorithm Peter’s JAVA code Nell’s JAVA code John’s JAVA code Algorithm translated into different languages Algorithm translated by different people

11. Programming shortcut Problem Problem Solving Phase (Algorithm) Implementation Phase (code) Shortcut? Think first and code later

12. JAVA program execution convert Java code to a form usable by computers provided that in a computer instructions and data are stored in the computer memories using binary codes In a computer, data represented by pulses of electricity On circuit => ‘1’; Off circuit => ‘0’ Data in binary form => combination of enough 1s and 0s Program execution means translating data and instructions to patterns of 1s and 0s.

13. Programming language levels Machine language Primitive instruction built into each machine Each type of CPU has its own language Binary based instructions => tedious process and prone to error Assembly language Short English like words for commands and data Tedious to use Both are considered to be low level languages

14. Programming language levels (cont’d) High level language Expressed in English like phrases Easier to read and write High level Language Assembly Language Machine Language a+bld [%fp-20] %o01101 000 0000 0111 ld [%fp-20] %o1 add %o0, %o1 1101 0010 0000 0111 1011 1111 1110 1000

15. Program development Software tools involved Editor: type a program and store in a file Translation from high level into executable form That translation may result in errors You change the code to fix the problem Execute the program and evaluate results Edit and save program Translate program Execute program errors

16. Compilers Translation into machine language Compiler: Translates code in one language  to equivalent code in another one Original code => source code, Target language => particular machine language Translate once and run whenever needed

17. Interpreters Translation into machine language Interpreter similar to compiler with some differences Interweaves the translation and execution Parts of the source code  are translated and executed one at a time Drawback:  Programs run more slowly,  as translation occurs during execution

18. JAVA translation and execution The process combines the use of a compiler and interpreter Java source code -> Bytecode (Java compiler) JAVA virtual machine reads bytecode and executes it Difference between Bytecode and machine language Bytecode is not tied to any particular processor type It makes JAVA architecture neutral => portable

19. JAVA translation and execution (cont’d) JAVA Source code JAVA compiler JAVA bytecode JAVA interpreter Bytecode compiler Machine code