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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.
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.
  [trainee@easterton cj]$


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 articles
J715 - Putting the Java Language Together
  [836] Build on what you already have with OO - (2006-08-17)
  [1181] Good Programming practise - where to initialise variables - (2007-05-09)
  [4326] Learning to program - comments, documentation and test code - (2014-11-22)
  [4430] The spirit of Java - delegating to classes - (2015-02-18)


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This is a page archived from The Horse's Mouth at http://www.wellho.net/horse/ - 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 our main site for current courses, prices, versions, etc - any mention of a price in "The Horse's Mouth" cannot be taken as an offer to supply at that price.

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