in this article, we will learn to load a file into the jshell session in java 9. we will learn about jshell and different ways we can load a file in jshell, which is the command line and the /open command.

what is a jshell?

jshell is a new command-line interactive repl (read-evaluate-print-loop) tool introduced in java 9 to evaluate declarations, statements, and expressions written in java. this tool also allows us to execute java code snippets and get immediate results.

loading a file into the jshell

there are two ways to load a file into the jshell session in java 9:

using command-line
using /open command

using command-line

sometimes, we have the code already written in a java file and are ready to execute it in jshell. we can run that code within the jshell by loading a file directly using the command-line.

for instance, i have created the "test1.java" file in the "c://temp" folder.

below is the code of the "test1.java" file:

class tutorialspoint
{
    public static void main(string[] argsv)
    {
    }

    public static void dosomething()
    {
        system.out.println("welcome to tutorials point");
    }
}

example

below is a code snippet for loading a file into the jshell using the command-line:

c:\temp>jshell test1.java
|  welcome to jshell -- version 9.0.4
|  for an introduction type: /help intro

jshell> tutorialspoint.dosomething()
welcome to tutorials point

in the code snippet, the "test1.java" file is directly loaded from the command-line, and the dosomething() function is called from the tutorialspoint method to print "welcome to tutorials point".

using /open command

to load a file into the jshell tool, we can use the "/open" command. files are executed in the order they are entered in the jshell session.

for instance, i have created the "test2.java" file in the "c://temp" folder. we can load the "test2.java" file into jshell by using the "/open" command.

below is the code of the "test2.java" file:

string s1 = "tutorialspoint";
string s2 = "tutorix";
string s3 = s1 + s2;

int sum(int a, int b) {
   return a + b;
}

int divide(int a, int b) {
   return a / b;
}

example

below is a code snippet for loading a file into the jshell using the "/open" command:

c:\users\user>jshell
| welcome to jshell -- version 9.0.4
| for an introduction type: /help intro

jshell> /open c:\temp\test2.java

jshell> /vars
|    string s1 = "tutorialspoint"
|    string s2 = "tutorix"
|    string s3 = "tutorialspointtutorix"

jshell> /methods
|    int sum(int,int)
|    int divide(int,int)

the "/open" command has loaded the "test2.java" file into a session. the "/vars" command can be used to load the variables into a session and "/methods" command can be used to load the methods into a session.

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