feat: linuxdistro jdk provider

src/main/java/dev/jbang/net/JdkManager.java

@@ -21,13 +21,7 @@
 
 import dev.jbang.Settings;
 import dev.jbang.cli.ExitException;
-import dev.jbang.net.jdkproviders.CurrentJdkProvider;
-import dev.jbang.net.jdkproviders.DefaultJdkProvider;
-import dev.jbang.net.jdkproviders.JBangJdkProvider;
-import dev.jbang.net.jdkproviders.JavaHomeJdkProvider;
-import dev.jbang.net.jdkproviders.PathJdkProvider;
-import dev.jbang.net.jdkproviders.ScoopJdkProvider;
-import dev.jbang.net.jdkproviders.SdkmanJdkProvider;
+import dev.jbang.net.jdkproviders.*;
 import dev.jbang.util.JavaUtil;
 import dev.jbang.util.Util;
 
@@ -36,7 +30,7 @@ public class JdkManager {
 
  // TODO Don't hard-code this list
  public static final String[] PROVIDERS_ALL = new String[] { "current", "default", "javahome", "path", "jbang",
- "sdkman", "scoop" };
+ "sdkman", "scoop", "linux" };
  public static final String[] PROVIDERS_DEFAULT = new String[] { "current", "default", "javahome", "path", "jbang" };
 
  public static void initProvidersByName(String... providerNames) {
@@ -74,6 +68,9 @@ public static void initProvidersByName(List<String> providerNames) {
  case "scoop":
  provider = new ScoopJdkProvider();
  break;
+ case "linux":
+ provider = new LinuxJdkProvider();
+ break;
  default:
  Util.warnMsg("Unknown JDK provider: " + name);
  continue;

src/main/java/dev/jbang/net/JdkProvider.java

@@ -121,7 +121,11 @@ default Jdk createJdk(@Nonnull String id, @Nullable Path home, @Nonnull String v
 
  default String name() {
  String nm = getClass().getSimpleName();
- return nm.substring(0, nm.length() - 11).toLowerCase();
+ if (nm.endsWith("JdkProvider")) {
+ return nm.substring(0, nm.length() - 11).toLowerCase();
+ } else {
+ return nm.toLowerCase();
+ }
  }
 
  /**

src/main/java/dev/jbang/net/jdkproviders/BaseFoldersJdkProvider.java

@@ -87,7 +87,7 @@ protected Path getJdkPath(@Nonnull String jdk) {
  return getJdksRoot().resolve(jdk);
  }
 
- private Predicate<Path> sameJdk(Path jdkRoot) {
+ protected Predicate<Path> sameJdk(Path jdkRoot) {
  Path release = jdkRoot.resolve("release");
  return (Path p) -> {
  try {
@@ -100,7 +100,7 @@ private Predicate<Path> sameJdk(Path jdkRoot) {
 
  protected Stream<Path> listJdkPaths() throws IOException {
  if (Files.isDirectory(getJdksRoot())) {
- return Files.list(getJdksRoot());
+ return Files.list(getJdksRoot()).filter(this::acceptFolder);
  }
  return Stream.empty();
  }
@@ -114,12 +114,16 @@ protected Path getJdksRoot() {
  protected Jdk createJdk(Path home) {
  String name = home.getFileName().toString();
  Optional<String> version = JavaUtil.resolveJavaVersionStringFromPath(home);
- if (version.isPresent()) {
+ if (version.isPresent() && acceptFolder(home)) {
  return createJdk(jdkId(name), home, version.get());
  }
  return null;
  }
 
+ protected boolean acceptFolder(Path jdkFolder) {
+ return Util.searchPath("javac", jdkFolder.resolve("bin").toString()) != null;
+ }
+
  protected boolean isValidId(String id) {
  return id.endsWith("-" + name());
  }

src/main/java/dev/jbang/net/jdkproviders/LinuxJdkProvider.java

@@ -0,0 +1,59 @@
+package dev.jbang.net.jdkproviders;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+/**
+ * This JDK provider is intended to detects JDKs that have been installed in
+ * standard location of the users linux distro.
+ *
+ * For now just using `/usr/lib/jvm` as apparently fedora, debian, ubuntu and
+ * centos/rhel use it.
+ *
+ * If need different behavior per linux distro its intended this provider will
+ * adjust based on identified distro.
+ *
+ */
+public class LinuxJdkProvider extends BaseFoldersJdkProvider {
+ private static final Path JDKS_ROOT = Paths.get("/usr/lib/jvm");
+
+ @Nonnull
+ @Override
+ protected Path getJdksRoot() {
+ return JDKS_ROOT;
+ }
+
+ @Nullable
+ @Override
+ protected String jdkId(String name) {
+ return name + "-linux";
+ }
+
+ @Override
+ public boolean canUse() {
+ return Files.isDirectory(JDKS_ROOT);
+ }
+
+ @Override
+ protected boolean acceptFolder(Path jdkFolder) {
+ return super.acceptFolder(jdkFolder) && !isSameFolderSymLink(jdkFolder);
+ }
+
+ // Returns true if a path is a symlink to an entry in the same folder
+ private boolean isSameFolderSymLink(Path jdkFolder) {
+ Path absFolder = jdkFolder.toAbsolutePath();
+ if (Files.isSymbolicLink(absFolder)) {
+ try {
+ Path realPath = absFolder.toRealPath();
+ return Files.isSameFile(absFolder.getParent(), realPath.getParent());
+ } catch (IOException e) {
+ /* ignore */ }
+ }
+ return false;
+ }
+}

src/test/java/dev/jbang/cli/TestJdk.java

@@ -451,9 +451,15 @@ private void initMockJdkDir(Path jdkPath, String version) {
 
  private void initMockJdkDir(Path jdkPath, String version, String key) {
  Util.mkdirs(jdkPath);
+ Path jdkBinPath = jdkPath.resolve("bin");
+ Util.mkdirs(jdkBinPath);
  String rawJavaVersion = key + "=\"" + version + "\"";
  Path release = jdkPath.resolve("release");
  try {
+ Path javacPath = jdkBinPath.resolve("javac");
+ Util.writeString(javacPath, "dummy");
+ javacPath.toFile().setExecutable(true, true);
+ Util.writeString(jdkBinPath.resolve("javac.exe"), "dummy");
  Util.writeString(release, rawJavaVersion);
  } catch (IOException e) {
  throw new RuntimeException(e);