Command line argument in java in eclipse

The main example used in these notes is the Welcome class,
developed in the WelcomeToJava Eclipse project.

This program accepts one input argument value,
which is automatically assigned to the first value
in String[] args , called args[0] .
(Computer people tend to count from 0 and not 1 .)

Study the program for a few minutes to find where args[0] is used.
Notice that it is of type String .

The detailed instructions are in the next section,
complete with screenshots from the Welcome class in Eclipse.

Two other example programs are described in the last section.

Detailed Instructions for Command Line Arguments in Eclipse
Example: Welcome.java

In the window shown below,
notice that the Welcome Java application is highlighted.

In the large subwindow of the Run window, there is a set of tabs,
labelled Main , Arguments , JRE , etc.
Notice that the Main tab is highlighted.

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For the Welcome program,
only one input argument value is needed:
the first name of a new Java student.
For this run, we have chosen Sarah as
the name of this student.

Notice where it has been typed in.
This is where all command line arguments should be entered.
These values remain the same for all runs,
until they are changed in this same window.

Another example is the Args class,
developed in the TestArgs Eclipse project. This program requires more than one command line argument.

For the Args program,
eight input argument values are needed.
For this run, we have chosen eight random sets of
characters, some numeric, some alphabetic, as input values:
namely, 101 , Joe , Larry , 93214 , 3.145 , 66 , ABCDEF , xxxxx .
Notice that there is at least one space between every two arguments.

Further Example of a Java programs using Command Line Arguments: TempConversion.java

Yet another example is the TempConversionCL class,
developed in the TempConversion Eclipse project. This program requires only one command line argument,
but this value must be converted from a String
to a double value to be used arithmetically.

For the TempConversionCL program,
only one input argument value is needed:
the value of the Celsius temperature.
For this run, we have chosen 28.5 for
this value of the Celsius temperature.

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how to add command line parameters when running java code in Eclipse?

How can I add command line parameters to the JVM in Eclipse? For example, let’s say I want to explicitly add -cp argument when running the JVM, is it possible? (I am giving it as an example, I realize I can add an external Jar to the project settings to get an additional classpath.) The argument I want to add is -agentlib:Shark (on Mac OSx for running a profiler).

3 Answers 3

You can specify vm arguments when creating a «Run Configuration» in Eclipse. Right-click on your project > Run Configuration > Java Application > Arguments tab.

Run —> Run Configurations —> Arguments

In the Run menu, there is an entry «Run Configurations», which allows you to configure everything about the spawned JVM. It has a tab to set the classpath, and another called «Arguments» where you can set JVM parameters.

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Tuesday, March 8, 2022

How to Pass Command Line Arguments in Eclipse

Eclipse is one of the most preferred IDE for Java/JEE development. Eclipse IDE provides various options like running the application from the IDE, providing arguments to your Java program, debugging your application. In this post we’ll see how to pass command line arguments to your Java program through Eclipse IDE.

Let’s take an example Java program where you have to add the two passed arguments and print the total.

public class Add < public static void main(String[] args) < try< if(args.length != 2)< throw new IllegalArgumentException("Argument length " + "should be 2 "); >>catch(IllegalArgumentException IAexp) < System.out.println("Error in the code - " + IAexp.getMessage()); >double total = Double.parseDouble(args[0]) + Double.parseDouble(args[1]); System.out.println("Sum of " + args[0] + " and " + args[1] + " is: " + total); > >

How to pass arguments in eclipse

You can select “Run Configuration” option by selecting the Run menu from the top menu.

You can also select the same “Run Configuration” option by right clicking the program for which you have to provide args, from the package explorer.

That will open the “Run Configuration” screen.

Make sure that the program where arguments are to be passed is selected.If you don’t find your program there search for it or add it by right clicking on “Java Application” and selecting New.

In the “Run Configuration” screen select the “Arguments” tab and provide required arguments in the “Program arguments” text area. Then select Apply and then Run to run you program.

That’s all for this topic How to Pass Command Line Arguments in Eclipse. If you have any doubt or any suggestions to make please drop a comment. Thanks!

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Command Line Arguments in Java

While we believe that this content benefits our community, we have not yet thoroughly reviewed it. If you have any suggestions for improvements, please let us know by clicking the “report an issue“ button at the bottom of the tutorial.

Command-line arguments in Java are used to pass arguments to the main program. If you look at the Java main method syntax, it accepts String array as an argument. When we pass command-line arguments, they are treated as strings and passed to the main function in the string array argument. The arguments have to be passed as space-separated values. We can pass strings and primitive data types as command-line arguments. The arguments will be converted to strings and passed into the main method string array argument.

Command Line Arguments in Java

package com.journaldev.examples; public class CommandLineArguments < public static void main(String[] args) < System.out.println("Number of Command Line Argument = "+args.length); for(int i = 0; i< args.length; i++) < System.out.println(String.format("Command Line Argument %d is %s", i, args[i])); >> >

$ java com/journaldev/examples/CommandLineArguments.java Number of Command Line Argument = 0

Now, let’s pass some arguments to the main class. We have to pass the arguments as space-separated values.

$ java com/journaldev/examples/CommandLineArguments.java "A" "B" "C" Number of Command Line Argument = 3 Command Line Argument 0 is A Command Line Argument 1 is B Command Line Argument 2 is C $ java com/journaldev/examples/CommandLineArguments.java 1 2 3 Number of Command Line Argument = 3 Command Line Argument 0 is 1 Command Line Argument 1 is 2 Command Line Argument 2 is 3 $

Note: If you are using Java 11 or higher, you don’t need to compile the java source file explicitly. The java command will compile and run the class simultaneously.

How to Pass Command Line Arguments in Eclipse

Step 1: Open the Class Run Configurations Settings

From the class editor, right click and chose “Run As” -> “Run Configurations…”.

Step 2: Specify the Program Arguments in the Arguments Tab

In the pop up window, click on the Arguments tab. Then provide the command line arguments value in the “Program Arguments” text box.

Step 3: Click on the Run button

When you will click on the Run button, the run configurations will be saved and the program will execute with the specified command-line arguments. If you run the class again, the saved run configuration will be used. So if you want to override the command-line arguments or remove them, you will have to open the run configurations window and make necessary changes.

Conclusion

The command-line arguments are used to provide values that are essential to run the program. For example, we can specify the database credentials to be used by the program. We can specify the configuration file location from where the program should pick the required values. Reference: Command-Line Arguments Oracle Docs

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Command line argument in java in eclipse