Eclipse (@ www.eclipse.org) is an open-source Integrated Development Environment (IDE) supported by IBM. Eclipse is popular for Java application development (Java SE and Java EE) and Android apps. It also supports C/C++, PHP, Python, Perl, and other web project developments via extensible plug-ins. Eclipse is cross-platform and runs under Windows, Linux and macOS.
Jul 17, 2016.
Eclipse Versions
The various versions are:
How to Install Eclipse IDE 2019-12 for Java DevelopersHow to Install Eclipse on WindowsStep 0: Install JDK
To use Eclipse for Java programming, you need to first install Java Development Kit (JDK). Read 'How to Install JDK for Windows'.
Step 1: Download
Download Eclipse from https://www.eclipse.org/downloads. Under 'Get Eclipse IDE 2019-12' ⇒ Click 'Download Packages'. For beginners, choose the 'Eclipse IDE for Java Developers' and 'Windows 64-bit' (e.g., '
eclipse-java-2019-12-R-win32-x86_64.zip ' - about 201MB) ⇒ Download.
Step 2: Unzip
To install Eclipse, simply unzip the downloaded file into a directory of your choice (e.g., '
c:myProject ').
I prefer the zip version, because there is no need to run any installer. Moreover, you can simply delete the entire Eclipse directory when it is no longer needed (without running any un-installer). You are free to move or rename the directory. You can install (unzip) multiple copies of Eclipse in the same machine.
How to Install Eclipse on macOS
To use Eclipse for Java programming, you need to first install JDK. Read 'How to install JDK for macOS'.
To install Eclipse:
How to Install Eclipse on Ubuntu Linux
Eclipse comes with many flavors (See 'Eclipse Packages' @ https://www.eclipse.org/downloads/compare.php):
Nonetheless, you can install any package, and then add more features when needed.
To install Eclipse (e.g, for Java Programming):
To run Eclipse, open the '
/usr/local/eclipse ' folder and click on the 'Eclipse' icon; or start a 'Terminal', enter 'eclipse'.
Lock Eclipse on Launcher
Simply start Eclipse. Right-click the Eclipse icon ⇒ Lock to Launcher.
(For older version - If the above don't work) Create a
/usr/share/applications/eclipse.desktop file with the following contents:
Start Eclipse, right-click on the Eclipse icon on launcher ⇒ lock to launcher.
Writing your First Java Program in EclipseStep 0: Launch Eclipse
Step 1: Create a new Java ProjectFor each Java application, you need to create a project to keep all the source files, classes and relevant resources.
To create a new Java project:
Step 2: Write a Hello-world Java Program
Step 3: Compile & Execute the Java Program
NOTES:
Correcting Syntax Errors
Eclipse performs incremented compilation, as and when a source 'line' is entered. It marked a source line having syntax error with a RED CROSS. Place your cursor at the RED CROSS to view the error message.
You CANNOT RUN the program if there is any syntax error (marked by a RED CROSS before the filename). Correct all the syntax errors; and RUN the program.
HINTS: In some cases, Eclipse shows a ORANGE LIGHT-BULB (for HINTS) next to the ERROR RED-CROSS (Line 5 in the above diagram). You can click on the LIGHT-BULB to get a list of HINTS to resolve this particular error, which may or may not work!
SYNTAX WARNING: marked by a orange triangular exclaimation sign. Unlike errors, warnings may or may not cause problems. Try to fix these warnings as well. But you can RUN your program with warnings.
Read the Eclipse Documentation
At a minimum, you SHOULD browse through Eclipse's 'Workbench User Guide' and 'Java Development User Guide' - accessible via the Eclipse's 'Welcome' page or 'Help' menu. This will save you many agonizing hours trying to figure out how to do somethings later.
Debugging Programs in Eclipse
Able to use a graphics debugger to debug program is crucial in programming. It could save you countless hours guessing on what went wrong.
Step 0: Write a Java Program
The following program computes and prints the factorial of
n (=1*2*3*...*n ). The program, however, has a logical error and produce a wrong answer for n =20 ('The Factorial of 20 is -2102132736 ' - a negative number?!).
Let's use the graphic debugger to debug the program.
Step 1: Set an Initial Breakpoint
A breakpoint suspends program execution for you to examine the internal states (e.g., value of variables) of the program. Before starting the debugger, you need to set at least one breakpoint to suspend the execution inside the program. Set a breakpoint at
main() method by double-clicking on the left-margin of the line containing main() . A blue circle appears in the left-margin indicating a breakpoint is set at that line.
Step 2: Start Debugger
Right click anywhere on the source code (or from the 'Run' menu) ⇒ 'Debug As' ⇒ 'Java Application' ⇒ choose 'Yes' to switch into 'Debug' perspective (A perspective is a particular arrangement of panels to suits a certain development task such as editing or debugging). The program begins execution but suspends its operation at the breakpoint, i.e., the
main() method.
As illustrated in the following diagram, the highlighted line (also pointed to by a blue arrow) indicates the statement to be executed in the next step.
Step 3: Step-Over and Watch the Variables and Outputs
Click the 'Step Over' button (or select 'Step Over' from 'Run' menu) to single-step thru your program. At each of the step, examine the value of the variables (in the 'Variable' panel) and the outputs produced by your program (in the 'Console' Panel), if any. You can also place your cursor at any variable to inspect the content of the variable.
Single-stepping thru the program and watching the values of internal variables and the outputs produced is the ultimate mean in debugging programs - because it is exactly how the computer runs your program!
Step 4: Breakpoint, Run-To-Line, Resume and Terminate
As mentioned, a breakpoint suspends program execution and let you examine the internal states of the program. To set a breakpoint on a particular statement, double-click the left-margin of that line (or select 'Toggle Breakpoint' from 'Run' menu).
'Resume' continues the program execution, up to the next breakpoint, or till the end of the program.
'Single-step' thru a loop with a large count is time-consuming. You could set a breakpoint at the statement immediately outside the loop (e.g., Line 11 of the above program), and issue 'Resume' to complete the loop.
Alternatively, you can place the cursor on a particular statement, and issue 'Run-To-Line' from the 'Run' menu to continue execution up to the line.
'Terminate' ends the debugging session. Always terminate your current debugging session using 'Terminate' or 'Resume' till the end of the program.
Step 5: Switching Back to Java perspective
Click the 'Java' perspective icon on the upper-right corner to switch back to the 'Java' perspective for further programming (or 'Window' menu ⇒ Open Perspective ⇒ Java).
Important: I can's stress more that mastering the use of debugger is crucial in programming. Explore the features provided by the debuggers.
Other Debugger's Features
Step-Into and Step-Return: To debug a method, you need to use 'Step-Into' to step into the first statement of the method. ('Step-Over' runs the function in a single step without stepping through the statements within the function.) You could use 'Step-Return' to return back to the caller, anywhere within the method. Alternatively, you could set a breakpoint inside a method.
Modify the Value of a Variable: You can modify the value of a variable by entering a new value in the 'Variable' panel. This is handy for temporarily modifying the behavior of a program, without changing the source code.
Tips & TricksGeneral Usages (for all Programming Tasks)
These are the features that I find to be most useful in Eclipse:
Update Eclipse and Install new Software
For Java Application Development Only
For Web Developers
File I/O in Eclipse
Suppose that your want to write a Java program, which inputs from a text file called '
xxxx.in ' and outputs to a text file called 'xxxx.out '. This is a little tricky under Eclipse due to:
This is a sample JDK 1.5 program for file input/output:
Create the input text file called '
FileIOTest.in ' with the following contents and terminated with a newline:
Writing Swing Applications using Eclipse GUI Builder
Eclipse provides a visual GUI builder called 'WindowBuilder' (@ https://www.eclipse.org/windowbuilder), which supports AWT/Swing, SWT (Eclipse's Standard Widget Toolkit - an alternative to JDK's AWT/Swing), XWT, GWT, eRCT.
Step 0: Install WindowBuilder
To install 'WindowBuilder', goto 'Help' ⇒ Install New Software ⇒ In 'Work with', enter 'https://download.eclipse.org/windowbuilder/latest/' (You can find the proper link from 'http://www.eclipse.org/windowbuilder/download.php') ⇒ Check 'WindowBuilder' ⇒ Next ⇒ Next ⇒ Accept the licence ⇒ Finish.
Step 1: Create a New 'Java Application' Project
Step 2: Create a Swing JFrame Subclass
Eclipse Generated Codes
Study the codes generated by Eclipse GUI Builder, as follows, which is just a typical Swing application.
Eclipse for C/C++ Programming
Here.
Eclipse PDT (PHP Development Tool)
Here.
Eclipse and Database Development (MySQL)
Reference: 'Data Tools Platform User Documentation' @ Eclipse Welcome page.
You need to install Eclipse for Java EE, MySQL and MySQL Connector/J Driver. Read 'How to install and get started with MySQL'.
To use Eclipse for MySQL development:
Developing and Deploying Web Applications in Eclipse for Java EESetting Up Eclipse for Web Development
Writing a Hello-world JSP Page
Writing a Hello-world Servlet
Exporting a Web Application as a WAR fileEclipse Workspace Download
Right-click on the project to be exported ⇒ Export ⇒ WAR File ⇒ In 'Destination', specify the destination directory and filename (the filename shall be the web application name) ⇒ Finish.
Writing a Hello-world JSF PageFree Download Eclipse Java Ide
[TODO]
Debugging Web ApplicationsEclipse Software Java
You can debug a webapp just like standalone application. For example, you can set breakpoints, single-step through the programs, etc.
REFERENCES & RESOURCES
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