Magercises: Java Basics


Introduction

These Magercises show how to create and run Java applications and applets, use strings and arrays in Java, how to create simple classes and methods, and how to create packages. Details about the semantics of equality and assignment in Java are also explored.

There are eight Magercises to complete:

  1. Hello World Application
    Type in a "Hello World" application from the course notes, compile it using the javac compiler and run it using java, the Java interpreter.

    Educational goal(s):

    • Compile and run a Java application
  2. Applet Parameters
    Modify the previous applet to print out its parameters.

    Educational goal(s):

    • Use of the APPLET and PARAM tags in HTML.
    • Reading of applet parameters.
  3. Reference Semantics in Java
    Some details of reference semantics in Java are explored by creating one-to-one relationships between some objects.

    Educational goal(s):

    • How objects are referenced in Java.
    • How maintain referential integrity between objects.
  4. Equality in Java
    Examine the semantics of equality in Java by performing searches on an array of objects.

    Educational goal(s):

    • Semantics of == and the equals method.
  5. Garbage Collection in Action
    Watch Java's garbage collector reclaim storage.

    Educational goal(s):

    • learn under what circumstances Java performs garbage collection.
    • learn that finalizers are not guaranteed to run.
    • learn how to force garbage collection.
  6. Working With Strings
    Learn how to do common string manipulations in Java.

    Educational goal(s):

    • Create new strings using concatenation.
    • Use of String constructors.
    • Use of the substring method.
    • Use of StringBuffers.
    • Conversion of basic types into Strings.
    • Conversion of Strings into numeric datatypes.
  7. Working With Arrays
    Create some arrays and and show how to do common array tasks.

    Educational goal(s):

    • Iterate through arrays.
    • Use the arraycopy method to copy arrays efficiently.
    • Creation and initialization of arrays.
  8. The Hashtable Class
    The array used for storage in previous magercises is replaced with a Hashtable.

    Educational goal(s):

    • Use of the Hashtable class.
    • Iteration using the Enumeration interface.
     


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