Java Pros and Cons Roundtable American Nuclear Society

Java Pros and Cons − Roundtable American Nuclear Society Annual Meeting June 16, 2004 Pittsburgh, PA OAK RIDGE NATIONAL LABORATORY U. S. DEPARTMENT OF ENERGY 1

Java – an Object-Oriented Programming Language · Based on objects: data and methods together · Four Concepts: - Abstraction – describes physical world Encapsulation – data and methods together Inheritance - just like something else but. . . Polymorphism – method overloading OAK RIDGE NATIONAL LABORATORY U. S. DEPARTMENT OF ENERGY 2

Abstraction / Encapsulation public class Particle { Position position; public class Position { Direction direction; double energy; double x, y, z; public Position(double a, double b, double c){ x = a; y = b; z = c; } public void x = x + y = y + z = z + } public Particle(){ position direction = new Position(1, 0, 0); energy = 1. 0; } move(Direction d, double dis){ d. u*dis; d. v*dis; d. w*dis; public void move(double distance){ position. move(direction, distance); } public double how. Far. To(Position p){ double answer = (p. x-x)*(p. x-x) + (p. y-y)*(p. y-y) + (p. z-z)*(p. z-z); answer = Math. sqrt( answer ); return answer; } } = new Position(0, 0, 0); public void scat(double t, double p){. . . } } OAK RIDGE NATIONAL LABORATORY U. S. DEPARTMENT OF ENERGY 3

Inheritance (1/2) public class Charged. Particle extends Particle { double rest. Mass; int charge; // Physical Constants static double ELEMCHARGE static double RESTMASSKG static double RESTMASS static double ERADIUS = = 1. 60217733 e-19; 9. 1093897 e-31; 0. 511; 2. 81792 e-15; // // Coulombs kg Me. V meter public Charged. Particle(){ super(); rest. Mass = Charged. Particle. RESTMASS; charge = -1; } public double get. Speed(){ double speed =. . . (energy-rest. Mass). . . return speed; } } OAK RIDGE NATIONAL LABORATORY U. S. DEPARTMENT OF ENERGY 4

Inheritance (2/2) public class Photon extends Particle { // Physical Constants static double speed. Of. Light = 299792458. 0; // m/s static double planck. Constant = 6. 6260755 e-34; // Joule seconds public Photon(){ super(); } public Particle[] compton. Scatter(){ Particle[] answer = new Particle[2]; // photoelectron answer[0] = new Charged. Particle(. . . ); // scattered photon answer[1] = new Photon(. . . ); return answer; } } OAK RIDGE NATIONAL LABORATORY U. S. DEPARTMENT OF ENERGY 5

Polymorphism public class Particle { Position position; Direction direction; double energy; public Particle(){ position = new Position(0, 0, 0); direction = new Position(1, 0, 0); energy = 1. 0; } public Particle(Position p, Direction d, double e){ position = p direction = d; energy = e; } public Particle(Particle p){ position = p. position; direction = p. direction; energy = p. energy; } } OAK RIDGE NATIONAL LABORATORY U. S. DEPARTMENT OF ENERGY 6

Java Pros · · Free, freely distributable Portable – “Write once, run anywhere” Internet savvy Extensive libraries – database, GUI, networking, etc. · Language – strongly typed, array indices are checked, automatic garbage collection, Threads, Exceptions · *. jar files – Java archive, runnable OAK RIDGE NATIONAL LABORATORY U. S. DEPARTMENT OF ENERGY 7

Java Cons · Interpreted OAK RIDGE NATIONAL LABORATORY U. S. DEPARTMENT OF ENERGY 8

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Java 1. 5 “Tiger” · Generics - no casting, errors at compile time, not runtime · Enhanced for Loop · Autoboxing/Unboxing collections of primitive data types · Formatted Output - more like C or FORTRAN · New JVM Profiling API · Improved Diagnostic Ability - get. Stack. Trace, Thread. get. All. Stack. Traces private void print. Collection(Collection c) { Iterator<String> i = c. iterator(); while(i. has. Next()) { String item = i. next(); System. out. println("Item: "+item); } } public void new. For(Collection<String> c) { for(String str : c) { System. out. println(str); } } System. out. printf("%s %3 d", name, age); OAK RIDGE NATIONAL LABORATORY U. S. DEPARTMENT OF ENERGY 18

Sun Microsystems, Inc. Binary Code License Agreement for the JAVATM 2 SOFTWARE DEVELOPMENT KIT (J 2 SDK), STANDARD EDITION, VERSION 1. 4. 2_X 3. RESTRICTIONS. . You acknowledge that Licensed Software is not designed or intended for use in the design, construction, operation or maintenance of any nuclear facility. . OAK RIDGE NATIONAL LABORATORY U. S. DEPARTMENT OF ENERGY 19

Sun Microsystems, Inc. Binary Code License Agreement for the JAVATM 2 SOFTWARE DEVELOPMENT KIT (J 2 SDK), STANDARD EDITION, VERSION 1. 4. 2_X 3. RESTRICTIONS. . You acknowledge that Licensed Software is not designed or intended for use in the design, construction, operation or maintenance of any nuclear facility. . OAK RIDGE NATIONAL LABORATORY U. S. DEPARTMENT OF ENERGY 20

Any Questions? OAK RIDGE NATIONAL LABORATORY U. S. DEPARTMENT OF ENERGY 21