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For 2021 - online Python 3 training - see ((here)).

Our plans were to retire in summer 2020 and see the world, but Coronavirus has lead us into a lot of lockdown programming in Python 3 and PHP 7.
We can now offer tailored online training - small groups, real tutors - works really well for groups of 4 to 14 delegates. Anywhere in the world; course language English.

Please ask about private 'maintenance' training for Python 2, Tcl, Perl, PHP, Lua, etc.

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Web Application Deployment module A502
Java - Basic Tools
Exercises, examples and other material relating to training module A502. This topic is presented on public courses Deploying Apache and Tomcat, Deploying Java Applications on Linux / Unix

This module introduces you to Java source code, class and jar files, and the tools used to produce and examine them.

Articles and tips on this subjectupdated
4412Java -making sure you have the right versions
"Java is a portable language" ... "The binary .class files will work across platform". And indeed they will - within limits. I was teaching Java earlier today, using a Linux operating system on one of our delegate machines, and this evening I'm writing up examples on my backroom laptop - a system that ...
3819Packing a tar, jar or war file - best practise
Scenario - a contact emails you a [tjw]ar file containing - let's say - 20 files within it. You unpack it in a directory that already has 15 files in it ... and you end up with 30 file. Hmm - not what you might have expected; you were expecting 35 files in total. What went wrong? Five of the files ...
3151Disassembling Python and Java - previously compiled code
Most modern languages translate the source code you give into an intermediate byte code prior to it being run, and in can sometimes be useful and instructive to reverse engineer the code to help to understand what's going on within the more arcane elements of the language. Some languages actually provide ...
2859Using java, javac, jar, and CLASSPATH - a simple example
What Version of Java am I running? How do I edit, compile and run a Java program? What does this error message mean? How do I puts lots of classes into a single file, then run them from that file? How do I see what's in that file? How do I get Java to look for a class it needs in a series of ...
2422Looking inside Java classes - javap and javadoc
javap is a program that looks inside a Java class and reports on all the methods and variables that are exposed by that class ... so it's looking at a Java class's object format. javadoc is a program that analyses Java source code and reports on all the methods that are exposed by that class. javap ...
2153Class Loading and Variable Conversion in Java
"Where did you get THAT from?" Ever heard that question? I've asked it of Java sometimes, in wondering where a Java virtual machine has found a class from ... and it's not always obvious. When loading a class, Java looks at each location given in the CLASSPATH in turn ... and if there are import ...
1909javax.servlet cannot be resolved - how to solve
Two common problems in compiling Servlets for use within a Tomcat container ... PROBLEM: My Java Compile of a Servlet says "javax.servlet cannot be resolved" For example: [trainee@easterton sources]$ javac Smallest.java ---------- 1. ERROR in Smallest.java  (at line 2)    import javax.servlet.*;           ^^^^^^^^^^^^^ The import javax.servlet cannot be resolved ---------- 2. ERROR in Smallest.java  (at line 3)    import javax.servlet.http.*;           ^^^^^^^^^^^^^ The import javax.servlet cannot be resolved ---------- 3. ERROR in Smallest.java  (at line 5)    public class Smallest extends HttpServlet {                                  ^^^^^^^^^^^ HttpServlet cannot be resolved to a type ---------- 4. ERROR in Smallest.java  (at line 9)    public void doGet(HttpServletRequest request,                      ^^^^^^^^^^^^^^^^^^ HttpServletRequest cannot be resolved to a type ---------- 5. ERROR in Smallest.java  (at line 10)    HttpServletResponse response)    ^^^^^^^^^^^^^^^^^^^ HttpServletResponse cannot be resolved to a type ---------- 6. ERROR in Smallest.java  (at line 11)    throws IOException, ServletException                        ^^^^^^^^^^^^^^^^ ServletException cannot be resolved to a type ---------- 6 problems (6 errors)[trainee@easterton sources]$ SOLUTION: ...
1771More HowTo diagrams - MySQL, Tomcat and Java
Here are some more diagrams "off the wall" from last week - showing "howto" and "whatis" information for Tomcat, Java and MySQL Some Tomcat and Java Fundamentals On the right of the board ... the main java programs ... • the Java compiler is called javac • the Java Virtual machins is in a ...
1562Java Compiler - needs all classes, compiles them all too
Remember that when you compile a java source file ... a) You must have the classes it will use when it runs available to the compiler so that it can check (a bit frustrating at times if you're compiling on one machine but going to be running on another) b) If you supply only java course code for some ...
1192What are WEB-INF and META-INF directories?
If you're looking at a web application on your Tomcat server you'll see all the files that you would expect - things like an index.html (or perhaps an index.jsp), images, and perhaps style sheets, a robots.txt and a favicon.ico. You'll also see a WEB-INF directory, and perhaps a META-INF directory that ...
1082Straight from the .jar
Disc drives have got much faster since my youth ... and processors at have got much much MUCH faster in the same period. So, 30 years ago, we used to compress files to store them on the disc when we knew we weren't likely to keep needing them, but we didn't compress them as a matter of course as we ...
754tar, jar, war, ear, sar files
Have you ever wondered why that are so many file extensions ending in "a r"? It's because the "ar" stands for archive, and it's such a reasonable way of naming file that the original tar which stands for tape archive was picked up by Sun and the Java community and transmuted into other file formats. tar ...
Examples from our training material
Annie.java   "Hello World" in Java
Bella.java   Running a method in Java
Chloe.java   Running a method from another class
Debbie.java   Class used in Chloe.java example
Passport.java   Passport class
Summer.java   Summer test program
javalog.001   Annotated log
Background information
Some modules are available for download as a sample of our material or under an Open Training Notes License for free download from [here].
Topics covered in this module
Compiling and running Java programs.
Applications with multiple classes.
Standard Classes.
.war files.
Examining Java files and classes.
Reference: Options to the Java utility commands.
Complete learning
If you are looking for a complete course and not just a information on a single subject, visit our Listing and schedule page.

Well House Consultants specialise in training courses in Linux and LAMP,Ruby, Lua, Python, Perl, PHP, and MySQL. We run Private Courses throughout the UK (and beyond for longer courses), and Public Courses at our training centre in Melksham, Wiltshire, England. It's surprisingly cost effective to come on our public courses - even if you live in a different country or continent to us.

We have a technical library of over 700 books on the subjects on which we teach. These books are available for reference at our training centre.

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