For 2023 - we are now fully retired from IT training.
We have made many, many friends over 25 years of teaching about Python, Tcl, Perl, PHP, Lua, Java, C and C++ - and MySQL, Linux and Solaris/SunOS too. Our training notes are now very much out of date, but due to upward compatability most of our examples remain operational and even relevant ad you are welcome to make us if them "as seen" and at your own risk.
Lisa and I (Graham) now live in what was our training centre in Melksham - happy to meet with former delegates here - but do check ahead before coming round. We are far from inactive - rather, enjoying the times that we are retired but still healthy enough in mind and body to be active!
I am also active in many other area and still look after a lot of web sites - you can find an index ((here))
Type checking, Java arrays and collections
Java's arrays are "typed" - you declare them to contain a particular type of primitive, or a particular type of object (which also enables them to contain any object type which is extended from that declared type).
But, when you go beyond arrays and use the more flexible utility classes such as ArrayLists, Vectors, HashTables, etc, you are declaring a container that can hold any
sort of object. So:
ArrayList Allwords = new ArrayList();
and you "worry" the Java Compiler:
[trainee@easterton cj]$ javac Utildemo.java
Note: Utildemo.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
You probably won't want to have this warning message crop up on every future compile (and, let's face it, Java is a real "maiden aunt" of a language when it comes to checking), so let's add in a request to make the checks in the declaration:
ArrayList<String> Allwords = new ArrayList<String>(); (written 2010-04-23)
Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articlesJ715 - Putting the Java Language Together 
Build on what you already have with OO - (2006-08-17) 
Good Programming practise - where to initialise variables - (2007-05-09) 
Learning to program - comments, documentation and test code - (2014-11-22) 
The spirit of Java - delegating to classes - (2015-02-18)
Some other Articles
Melksham ScoutsWhat is all this SESSION stuff about? (PHP)Improving your function calls (APIs) - General and PHPPerl Course FAQType checking, Java arrays and collectionsfor and foreach in JavaTravel Troubles and Jesus againAsking about JesusTraining Courses - time of changeBird Watching on the Melksham Avon
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This is a page archived from The Horse's Mouth at
the diary and writings of Graham Ellis.
Every attempt was made to provide current information at the time the
page was written, but things do move forward in our business - new software
releases, price changes, new techniques. Please check back via
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