Better classpath detection and remove the needs of Java options

README.md

@@ -1,10 +1,15 @@
 # jshell-gradle-plugin
-This gradle plugin helps you to explore your code and dependency in your gradle project with in jshell -- the official Java REPL tool.
+
+This gradle plugin helps you to explore your code and dependencies in your gradle project
+with in [jshell](https://docs.oracle.com/javase/9/jshell/introduction-jshell.htm) -- the official Java REPL tool.
 
 Hosted on https://plugins.gradle.org/plugin/net.java.openjdk.shinyafox.jshell.gradle.plugin
 
+
 ## Getting started
+
 To use this plugin, add following to your `build.gradle`:
+
 ```
 buildscript {
   repositories {
@@ -31,11 +36,22 @@ plugins {
 
 Task `jshell` is now enabled, which execute jshell with your classes and dependencies after compiling your code.
 
-Currently we need to run the task with some hacks for JDK9.
-Add a path for your jdk9 to `JAVA_HOME` and some options to JAVA_OPTS, and run task `jshell` with `--no-daemon --console plain` for gradle options.
+You need to run the task `jshell` with the options `--no-daemon --console plain`.
 Following is an example with gradlew:
+
 ```
-JAVA_HOME=/path/to/your/jdk9 \
-JAVA_OPTS="--add-exports jdk.jshell/jdk.internal.jshell.tool=ALL-UNNAMED --add-opens java.base/java.lang=ALL-UNNAMED"\
 ./gradlew --no-daemon --console plain jshell
 ```
+
+If you see this warning and the jshell console does not detect your classes:
+
+> :jshell task :classes not found, be sure to compile the project first
+
+Means the `classes` task needed to compile your project before launch `jshell`
+does not exist, just append the task needed to compile the project,
+some time is the same `classes` task but is not detected in multi-modules
+projects, so you need to add it explicitly in the Gradle command:
+
+```
+./gradlew --no-daemon --console plain classes jshell
+```

src/main/groovy/net/java/openjdk/shinyafox/jshell/gradle/plugin/JShellGradlePlugin.groovy

@@ -1,32 +1,36 @@
 package net.java.openjdk.shinyafox.jshell.gradle.plugin
 
-import java.io.File
-import jdk.internal.jshell.tool.JShellToolProvider
-
+import jdk.jshell.tool.JavaShellToolBuilder
 import org.gradle.api.Plugin
 import org.gradle.api.Project
-import org.gradle.api.tasks.compile.JavaCompile
-
-import java.nio.file.Files
-import java.nio.file.Paths
+import org.gradle.api.tasks.JavaExec
 
 class JShellGradlePlugin implements Plugin<Project> {
 
     @Override
     void apply(Project project) {
-        project.tasks.create('jshell')
-        .dependsOn("classes")
-        .doLast {
-            def path
-            project.tasks.withType(JavaCompile) {
-                path = classpath.findAll{ it.exists() }.join(
-                    System.properties['os.name'].toLowerCase().contains('windows') ? ';' : ':'
-                )
+        def jshellTask = project.tasks.create('jshell')
+        def classesTask = project.tasks.find { it.name == "classes" }
+        if (classesTask) {
+            jshellTask.dependsOn classesTask
+        } else {
+            // Some multi-module projects may not have the :classes task
+            jshellTask.logger.warn ":jshell task :classes not found, be sure to compile the project first"
+        }
+        jshellTask.doLast {
+            Set pathSet = []
+            project.tasks.withType(JavaExec) {
+                pathSet.addAll(classpath.findAll{ it.exists() })
+            }
+            project.subprojects.each {
+                it.tasks.withType(JavaExec) {
+                    pathSet.addAll(classpath.findAll{ it.exists() })
+                }
             }
-
             Thread.currentThread().setContextClassLoader(ClassLoader.getSystemClassLoader()) // promote class loader
-            JShellToolProvider.main((String[])["--class-path", path].toArray());
+            def path = pathSet.join(System.properties['os.name'].toLowerCase().contains('windows') ? ';' : ':')
+            jshellTask.logger.debug(":jshell executing with --class-path \"{}\"", path)
+            JavaShellToolBuilder.builder().run((String[])["--class-path", path].toArray())
         }
     }
-
 }