Tip Bank

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A HashMap of HashMaps

Question: I have been looking everywhere for information on HashMaps,particularly how to put one hash map into another HashMap. Answer: This is where the expression RTFM (Read That Fine Manual)

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Stopping Threads

Question: How do you stop a Thread without using the stop() method? Answer: The recommended method for stopping threads in Java is for each thread topoll a boolean value or

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Multiple Drawing Threads

Question: I have written an applet which uses a Graphics object to draw movingcircles. However, when multiple threads accesses the same Graphics object,the circles disappear after being on screen for

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Determining Stack Content Type

Question: Only Objects can be popped from, or push onto, a stack. That means Ihave to wrap a primitive data type, such as int, with something akin toInteger before pushing

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Switching Between Frames

Question: I’m building an application that has several different frames. Eachhas a button that when pressed should bring up a new frame and closethe calling frame. How can I display

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Altering the Substitution Character in SQL*Plus

When you are inserting data into Oracle tables in SQL*Plus using hard-coded string, some of the character fields may contain the ampersand character (&). The following is an example: insert

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Indexing Foreign Key Columns in Child Tables

Although an index is not mandatory on your foreign keys, if they are not indexed you will cause additional locking when certain Data Manipulation Language statements are executed against the

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Pre-Compiled Database Triggers

Many programmers create stored procedures out of large bodies of database trigger codes. This has primarily been because while stored procedures are stored in compiled form, database triggers are compiled