Java and Project Delivery E&CE 250 Winter

Java on Polaris We are using the Java 2 Version 1.3 SDK java -version It provides the following tools: javac java javadoc jar jdb appletviewer The compiler for the Java programming language The launcher for Java applications API document generation Creation and management of Java Archive files The Java Debugger The launcher for Java applets

Setting up 1.Log onto Polaris 2.Open the MS-DOS prompt from Windows 3. Create a ece250 directory in n:\ n:\ mkdir ece Edit n:\privexec.bat and add the lines: set PATH=%PATH%;q:\eng\ece\jdk1.3\bin set CLASSPATH = N:\ece Run the batch file n:\privexec.bat again

Java program: StringOperations Use any text editor you like Enter the following program: public class StringOperations { public static void main (String[] args) { String str = “If there were dreams to sell, What would you buy?”; System.out.println (“The string is: ” + str); System.out.println (“The length is: ” + str.length()); System.out.println (“Substring 14-20: ” + str.substring(14,20)); System.out.println (“Uppercase is: ” + str.toUpperCase()); } Save the program as StringOperations.java in your n:\ece250 directory

Compile the program Open the MS-DOS prompt and change your directory: n:\> cd ece250 Now compile the program: n:\ece250> javac StringOperations.java If everything works, you’ll get no messages back Check to see if a StringOperations.class file has been created. n:\ece250> dir *.class Note: For a Java program to compile properly, the name of the file and class defined must be the same. Remember: file name = class name.

Run the program Now run the program: n:\ece250> java StringOperations If it works, you’ll see: The string is: If there were dreams to sell, What would you buy? The length is: 49 Substring 14-20: dreams Uppercase is: IF THERE WERE DREAMS TO SELL, WHAT WOULD YOU BUY? If it fails, you’ll probably see: Exception in thread “main” java.lang.NoClassDefFoundError: StringOperations This will happen if you forgot to set the classpath to include your working directory.

javadoc A brief introduction to javadoc: –The purpose of this tool is to automatically generate HTML documentation from your.java source files. –You can run Javadoc on individual.java files, or.jar files –A comment must be added before the section it is commenting

The documentation is created by adding special tags in your.java files. These tags enable you to document your source code. The tags start with an "at" sign and are case-sensitive (they must be typed with the lowercase letters as shown) Some common javadoc

/** * The StringOperations class represents manipulation of strings Ricardo Rolon 1.0, Sep 2001 */ public class StringOperations { /** * Creates a String object. */ public static void main (String[] args) { String str = “If there were dreams to sell, What would you buy?”; System.out.println (“The string is: ” + str); System.out.println (“The length is: “ + str.length()); System.out.println (“Substring 14-20: “+ str.substring(14,20)); System.out.println (“Uppercase is: “ + str.toUpperCase()); } javadoc Example Javadoc -author -version StringOperations.java

Jar files The jar tool allows you to create archives, similar to a.zip archive. (In fact, they are based on ZIP compression) There are several reasons we want to do this: –easier to transfer (compressed files = less time over a network) –easier to execute (all the.class files are in the.jar, makes only one connection to the server) –jar’s can be signed by the author (security) –can store additional files like.html, readmes, etc.

Jar files Example: jar cvmf myManifestFile myJarFile *.class *.html *.java Where c option indicates that a jar file must be created, v means to be Verbose m include my own Manifest file f put the.jar file in a separate File whose name is provided The Java Virtual Machine needs to know which.class file in the.jar file contains the main( ) method. To do that, create a text file with just one line: Main-Class: For instance, in Project 1, if Rational.class is the class that contains main(), then MyManifestFile should contain the following line: Main-Class: Rational Don’t forget to end the Main-Class line with a carriage return, otherwise jar will not recognize it.

jdb (java debugger) Compile the program with the -g option (extra class info) Start jdb java debugger Set breakpoints Run program Experiment with debugger commands: –list -- Displays the source code of the line and several lines around it –locals -- List the values of local variables that are currently in use –print -- Display the value of the variable, object, array –step -- Executes the next line and stops again –cont -- Continues running the program –!! -- repeats the previous debugger command. After debugging the program, recompile the program without the -g option.

jdb --A debugging example 1. Compile the program: javac -g StringOperations.java 2. Start the debugger: jdb StrigOperations 3. Set breakpoints: stop in StringOperations.main stop at StringOperations:15 4. Run program: run StringOperations 5. Extract debugging info with commands: list, locals, print, step, cont 6. Recompile the program: javac StringOperations.java

Free Java Tools JBuilder, Borland. VisualAge for Java, IBM. Forte for Java ( Sun Microsystems. JCreator, JEditor, etc. No native methods!! Keep this in mind: We have to be able to compile it and run it on the Java 2 SDK 1.3 platform

Vector Vector is a web-based application course administration E&CE 250 will use Vector for the following: –Tracking of your marks for Projects –Electronic submission of your Projects Every student in this course has an account in Vector. Use your Polaris userid to login, and your ID # as your initial password. Change your password immediately.

Submitting files with Vector Project 1-3 –individual submission, under studentID Project 4 –group submission, under groupID [even if group of one student]

Project 1-3: Naming of.jar files Name the file as your numeric Student id followed by pn where n is the project number. (That is, just p1.jar) In Vector, the file name will be prep ended by your Polaris account For example: If your Polaris userid is “student1” then this will upload the file as student1_ p1.jar

Project 4: Naming of.jar files Send to ece250 with group membership by signup due date (even if group of 1). You will get your GroupID by . Name the file as your GroupID followed by p4 where n is the project number. (If the GroupID is E250G007, use E250G007p4.jar) In Vector, the file name will be prepended by your GroupID For the above example, the file will be uploaded as E250G007_E250G007p4.jar

Please post common questions on the ECE 250 newsgroup You can also send us , phone us, or drop by during office hours Make sure you give yourself lots of time. Recomendations