Is there a way to change the module path and add modules for a JShell program instance?

Question

I am trying to run Java code at runtime through a JShell instance created using the JShell API . To demonstrate my problem, I am going to share my simple code.

With my current setup, I have a lib directory in which there is a Java Java driver: mysql-connector-java-5.1.35.jar.

Starting JShell with a command tool and adding the required module as:

jshell --module-path lib --add-modules mysql.connector.java

and then loading the mysql driver works for me:

jshell> Class.forName("com.mysql.jdbc.Driver").newInstance();
$1 ==> com.mysql.jdbc.Driver@42f93a98

---

I created a similar Java 9 module with module-info.javalike:

module example.loadmysql {
    requires java.sql;
    requires mysql.connector.java;
    requires jdk.jshell;
}

src / example / loadmysql / Runner.java as:

package example.loadmysql;

import jdk.jshell.*;
import java.sql.*;

public class Runner {
    public static void main(String[] args) throws Exception {
        // this works because this module requires mysql.connector.java
        System.out.println(Class.forName("com.mysql.jdbc.Driver").newInstance());

        JShell js = JShell.create();
        String code = ""
            + "try {"
            + "    Class.forName(\"com.mysql.jdbc.Driver\").newInstance();"
            + "} catch (Exception e) {"
            + "    System.out.println(e.toString());"
            + "}";
        js.eval(code);
    }
}

After assembly / packaging:

java -p lib -m example.loadmysql
com.mysql.jdbc.Driver@6a4f787b
java.lang.ClassNotFoundException: com.mysql.jdbc.Driver

---

, example.loadmysql mysql, JShell . .

, JShell, JShell?

UPDATE. , :

String modulePath = System.getProperty("jdk.module.path");
js.eval("System.setProperty(\"jdk.module.path\", \""
    + modulePath + "\");");

. - .

Answer 1

addToClassPath eval :

JShell js = JShell.create();
js.addToClasspath("path/to/add/to/the/classpath");
String code = ""
        + "try {"
        + "    Class.forName(\"com.mysql.jdbc.Driver\").newInstance();"
        + "} catch (Exception e) {"
        + "    System.out.println(e.toString());"
        + "}";
js.eval(code);

, eval(). , , eval(String).

, , JShell eval, , - .

---

, , , mysql-connector-java-5.1.35.jar , , , , com.mysql.jdbc.Driver .

---

: - , , , Jshell.Builder compilerOptions, , ( ) -

JShell js = JShell.builder()
                 .compilerOptions("--module-path lib","--add-modules mysql.connector.java").build();
String code = ""
    + "try {"
    + "    Class.forName(\"com.mysql.jdbc.Driver\").newInstance();"
    + "} catch (Exception e) {"
    + "    System.out.println(e.toString());"
    + "}";
js.eval(code);

Answer 2

/env , . :

/env [-class-path <path>] [-module-path <path>] [-add-modules <modules>] ...
|   view or change the evaluation context

:

jshell> /help context
|  
|  context
|  
|  These options configure the evaluation context, they can be specified when
|  jshell is started: on the command-line, or restarted with the commands /env,
|  /reload, or /reset.
|  
|  They are:
|   --class-path <class search path of directories and zip/jar files>
|       A list of directories, JAR archives,
|       and ZIP archives to search for class files.
|       The list is separated with the path separator
|       (a : on unix/linux/mac, and ; on windows).
|   --module-path <module path>...
|       A list of directories, each directory
|       is a directory of modules.
|       The list is separated with the path separator
|       (a : on unix/linux/mac, and ; on windows).
|   --add-modules <modulename>[,<modulename>...]
|       root modules to resolve in addition to the initial module.
|       <modulename> can also be ALL-DEFAULT, ALL-SYSTEM,
|       ALL-MODULE-PATH.
|   --add-exports <module>/<package>=<target-module>(,<target-module>)*
|       updates <module> to export <package> to <target-module>,
|       regardless of module declaration.
|       <target-module> can be ALL-UNNAMED to export to all
|       unnamed modules. In jshell, if the <target-module> is not
|       specified (no =) then ALL-UNNAMED is used.
|  
|  On the command-line these options must have two dashes, e.g.: --module-path
|  On jshell commands they can have one or two dashes, e.g.: -module-path