visual basic barcode printing 7: Objects and Collections in Java

Creator PDF417 in Java 7: Objects and Collections

7: Objects and Collections
Recognizing PDF417 In Java
Using Barcode Control SDK for Java Control to generate, create, read, scan barcode image in Java applications.
PDF-417 2d Barcode Encoder In Java
Using Barcode encoder for Java Control to generate, create PDF 417 image in Java applications.
But since a LinkedHashMap loses the natural order (replacing it with lastaccessed order), if we need to list the parts by serial number, we ll have to explicitly sort the collection, using a utility method.
PDF 417 Recognizer In Java
Using Barcode recognizer for Java Control to read, scan read, scan image in Java applications.
Barcode Maker In Java
Using Barcode generator for Java Control to generate, create barcode image in Java applications.
Now that you know how to compare, organize, access, and sort objects, there s only one thing left to learn in this sequence: how to get rid of objects. The last objective in this chapter looks at the garbage collection system in Java. You simply won t believe how many garbage collection questions are likely to show up on your exam, so pay close attention to this last section. Most importantly, you ll need to know what is and is not guaranteed and what you re responsible for when it comes to memory management in Java.
Recognizing Barcode In Java
Using Barcode recognizer for Java Control to read, scan read, scan image in Java applications.
PDF-417 2d Barcode Encoder In Visual C#.NET
Using Barcode drawer for Visual Studio .NET Control to generate, create PDF-417 2d barcode image in VS .NET applications.
CERTIFICATION OBJECTIVE
Printing PDF 417 In .NET Framework
Using Barcode creator for ASP.NET Control to generate, create PDF417 image in ASP.NET applications.
Generating PDF417 In Visual Studio .NET
Using Barcode drawer for .NET framework Control to generate, create PDF417 image in .NET framework applications.
Garbage Collection (Exam Objectives 3.1, 3.2, 3.3)
PDF 417 Generation In VB.NET
Using Barcode drawer for Visual Studio .NET Control to generate, create PDF417 image in .NET framework applications.
Generate 2D Barcode In Java
Using Barcode creator for Java Control to generate, create Matrix 2D Barcode image in Java applications.
State the behavior that is guaranteed by the garbage collection system. Write code that explicitly makes objects eligible for garbage collection. Recognize the point in a piece of source code at which an object becomes eligible for garbage collection.
USS Code 39 Generator In Java
Using Barcode drawer for Java Control to generate, create Code 3 of 9 image in Java applications.
Encode GS1 DataBar-14 In Java
Using Barcode maker for Java Control to generate, create GS1 DataBar Limited image in Java applications.
Overview of Memory Management and Garbage Collection
EAN / UCC - 14 Generator In Java
Using Barcode creator for Java Control to generate, create EAN - 14 image in Java applications.
Drawing Bar Code In Visual C#
Using Barcode drawer for .NET framework Control to generate, create barcode image in VS .NET applications.
This is the section you ve been waiting for! It s finally time to dig into the wonderful world of memory management and garbage collection. Memory management is a crucial element in many types of applications. Consider a program that reads in large amounts of data, say from somewhere else on a network, and then writes that data into a database on a hard drive. A typical design would be to read the data into some sort of collection in memory, perform some operations on the data, and then write the data into the database. After the data is written into the database, the collection that stored the data temporarily must be emptied of old data or deleted and re-created before processing the next batch. This operation might be performed thousands of times, and in languages like C or C++ that do not offer automatic garbage collection, a small flaw in the logic that manually empties or deletes the collection data structures can allow small amounts of memory to be
GTIN - 13 Creation In None
Using Barcode printer for Font Control to generate, create EAN-13 image in Font applications.
Bar Code Decoder In VS .NET
Using Barcode Control SDK for ASP.NET Control to generate, create, read, scan barcode image in ASP.NET applications.
Garbage Collection (Exam Objectives 3.1, 3.2, 3.3)
Decode Bar Code In C#.NET
Using Barcode scanner for .NET framework Control to read, scan read, scan image in VS .NET applications.
Bar Code Reader In Visual Basic .NET
Using Barcode scanner for Visual Studio .NET Control to read, scan read, scan image in .NET framework applications.
improperly reclaimed or lost. Forever. These small losses are called memory leaks, and over many thousands of iterations they can make enough memory inaccessible that programs will eventually crash. Creating code that performs manual memory management cleanly and thoroughly is a nontrivial and complex task, and while estimates vary, it is arguable that manual memory management can double the development effort for a complex program. Java s garbage collector provides an automatic solution to memory management. In most cases it frees you from having to add any memory management logic to your application. The downside to automatic garbage collection is that you can t completely control when it runs and when it doesn t.
Generate Code-128 In Java
Using Barcode generator for BIRT reports Control to generate, create USS Code 128 image in BIRT reports applications.
Data Matrix 2d Barcode Encoder In Java
Using Barcode creation for BIRT Control to generate, create DataMatrix image in Eclipse BIRT applications.
Overview of Java s Garbage Collector
Let s look at what we mean when we talk about garbage collection in the land of Java. From the 30,000 ft. level, garbage collection is the phrase used to describe automatic memory management in Java. Whenever a software program executes (in Java, C, C++, Lisp, etc.), it uses memory in several different ways. We re not going to get into Computer Science 101 here, but it s typical for memory to be used to create a stack, a heap, in Java s case constant pools, and method areas. The heap is that part of memory where Java objects live, and it s the one and only part of memory that is in any way involved in the garbage collection process.
A heap is a heap is a heap. For the exam it s important to know that you can call it the heap, you can call it the garbage collectible heap, you can call it Johnson, but there is one and only one heap.
So, all of garbage collection revolves around making sure that the heap has as much free space as possible. For the purpose of the exam, what this boils down to is deleting any objects that are no longer reachable by the Java program running. We ll talk more about what reachable means, but let s drill this point in. When the garbage collector runs, its purpose is to find and delete objects that cannot be reached. If you think of a Java program as in a constant cycle of creating the objects it needs (which occupy space on the heap), and then discarding them when they re no longer needed, creating new objects, discarding them, and so on, the missing piece of the puzzle is the garbage collector. When it runs, it looks for those discarded objects and deletes them from memory so that the cycle of using memory and releasing it can continue. Ah, the great circle of life.
Copyright © OnBarcode.com . All rights reserved.