Improve the java executable location logic, #241

bom/pom.xml

@@ -70,6 +70,7 @@
         <jboss-metadata-web.version>11.0.0.Final</jboss-metadata-web.version>
         <maven-core.version>3.5.4</maven-core.version>
         <maven-resolver.version>1.1.1</maven-resolver.version>
+        <maven-toolchain.version>3.0-alpha-2</maven-toolchain.version>
         <guava.version>27.0.1-jre</guava.version>
         <plexus-utils.version>3.0.24</plexus-utils.version>
         <maven-plugin-annotations.version>3.5.2</maven-plugin-annotations.version>
@@ -940,6 +941,17 @@
                 <artifactId>maven-settings-builder</artifactId>
                 <version>${maven-core.version}</version>
             </dependency>
+            <dependency>
+                <groupId>org.apache.maven</groupId>
+                <artifactId>maven-toolchain</artifactId>
+                <version>${maven-toolchain.version}</version>
+                <exclusions>
+                    <exclusion>
+                        <groupId>org.codehaus.plexus</groupId>
+                        <artifactId>plexus-classworlds</artifactId>
+                    </exclusion>
+                </exclusions>
+            </dependency>
 
             <dependency>
                 <groupId>org.apache.maven.plugin-tools</groupId>

devtools/maven/pom.xml

@@ -46,6 +46,10 @@
             <groupId>org.apache.maven</groupId>
             <artifactId>maven-core</artifactId>
         </dependency>
+        <dependency>
+            <groupId>org.apache.maven</groupId>
+            <artifactId>maven-toolchain</artifactId>
+        </dependency>
 
         <dependency>
             <groupId>org.apache.maven.plugin-tools</groupId>

devtools/maven/src/main/java/io/quarkus/maven/DevMojo.java

@@ -19,7 +19,11 @@
 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.IOException;
-import java.net.*;
+import java.net.InetAddress;
+import java.net.MalformedURLException;
+import java.net.Socket;
+import java.net.URI;
+import java.net.URL;
 import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -31,16 +35,21 @@
 import java.util.zip.ZipOutputStream;
 
 import org.apache.maven.artifact.Artifact;
-import org.apache.maven.artifact.versioning.DefaultArtifactVersion;
 import org.apache.maven.execution.MavenSession;
 import org.apache.maven.model.Plugin;
 import org.apache.maven.model.PluginExecution;
 import org.apache.maven.model.Resource;
 import org.apache.maven.plugin.AbstractMojo;
 import org.apache.maven.plugin.MojoExecutionException;
 import org.apache.maven.plugin.MojoFailureException;
-import org.apache.maven.plugins.annotations.*;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.LifecyclePhase;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.plugins.annotations.ResolutionScope;
 import org.apache.maven.project.MavenProject;
+import org.apache.maven.toolchain.Toolchain;
+import org.apache.maven.toolchain.ToolchainManager;
 
 import io.quarkus.dev.ClassLoaderCompiler;
 import io.quarkus.dev.DevModeMain;
@@ -116,6 +125,17 @@ public class DevMojo extends AbstractMojo {
     @Parameter(defaultValue = "${preventnoverify}")
     private boolean preventnoverify = false;
 
+    @Component
+    private ToolchainManager toolchainManager;
+
+    public ToolchainManager getToolchainManager() {
+        return toolchainManager;
+    }
+
+    public MavenSession getSession() {
+        return session;
+    }
+
     @Override
     public void execute() throws MojoFailureException, MojoExecutionException {
         mavenVersionEnforcer.ensureMavenVersion(getLog(), session);
@@ -148,7 +168,9 @@ public void execute() throws MojoFailureException, MojoExecutionException {
 
         try {
             List<String> args = new ArrayList<>();
-            args.add("java");
+            String javaTool = findJavaTool();
+            getLog().info("Using javaTool: " + javaTool);
+            args.add(javaTool);
             if (debug == null) {
                 // debug mode not specified
                 // make sure 5005 is not used, we don't want to just fail if something else is using it
@@ -302,6 +324,62 @@ public void run() {
         }
     }
 
+    /**
+     * Search for the java command in the order:
+     * 1. maven-toolchains plugin configuration
+     * 2. java.home location
+     * 3. java[.exe] on the system path
+     *
+     * @return the java command to use
+     */
+    protected String findJavaTool() {
+        String java = null;
+
+        // See if a toolchain is configured
+        if (getToolchainManager() != null) {
+            Toolchain toolchain = getToolchainManager().getToolchainFromBuildContext("jdk", getSession());
+            if (toolchain != null) {
+                java = toolchain.findTool("java");
+                getLog().info("JVM from toolchain: " + java);
+            }
+        }
+        if (java == null) {
+            // use the same JVM as the one used to run Maven (the "java.home" one)
+            java = System.getProperty("java.home") + File.separator + "bin" + File.separator + "java";
+            File javaCheck = new File(java);
+            getLog().debug("Checking: " + javaCheck.getAbsolutePath());
+            if (!javaCheck.canExecute()) {
+                getLog().debug(javaCheck.getAbsolutePath() + " is not executable");
+
+                java = null;
+                // Try executable extensions if windows
+                if (OS.determineOS() == OS.WINDOWS && System.getenv().containsKey("PATHEXT")) {
+                    String extpath = System.getenv("PATHEXT");
+                    String[] exts = extpath.split(";");
+                    for (String ext : exts) {
+                        File winExe = new File(javaCheck.getAbsolutePath() + ext);
+                        getLog().debug("Checking: " + winExe.getAbsolutePath());
+                        if (winExe.canExecute()) {
+                            java = winExe.getAbsolutePath();
+                            getLog().debug("Executable: " + winExe.getAbsolutePath());
+                            break;
+                        }
+                    }
+                }
+                // Fallback to java on the path
+                if (java == null) {
+                    if (OS.determineOS() == OS.WINDOWS) {
+                        java = "java.exe";
+                    } else {
+                        java = "java";
+                    }
+                }
+            }
+        }
+        getLog().debug("findJavaTool, selected JVM: " + java);
+        return java;
+    }
+
     private void addToClassPaths(StringBuilder classPathManifest, StringBuilder classPath, File file)
             throws MalformedURLException {
         URI uri = file.toPath().toAbsolutePath().toUri();
@@ -315,4 +393,44 @@ private void addToClassPaths(StringBuilder classPathManifest, StringBuilder clas
         classPath.append(" ");
     }
 
+    /**
+     * Enum to classify the os.name system property
+     */
+    static enum OS {
+        WINDOWS, LINUX, MAC, OTHER;
+
+        private String version;
+
+        public String getVersion() {
+            return version;
+        }
+
+        public void setVersion(String version) {
+            this.version = version;
+        }
+
+        static OS determineOS() {
+            OS os = OS.OTHER;
+            String osName = System.getProperty("os.name");
+            osName = osName.toLowerCase();
+            if (osName.contains("windows")) {
+                os = OS.WINDOWS;
+            } else if (osName.contains("linux")
+                    || osName.contains("freebsd")
+                    || osName.contains("unix")
+                    || osName.contains("sunos")
+                    || osName.contains("solaris")
+                    || osName.contains("aix")) {
+                os = OS.LINUX;
+            } else if (osName.contains("mac os")) {
+                os = OS.MAC;
+            } else {
+                os = OS.OTHER;
+            }
+
+            os.setVersion(System.getProperty("os.version"));
+            return os;
+        }
+    }
+
 }