Fix embedded JDK LICENSE handling for JDK 9

PiperOrigin-RevId: 196583301
Change-Id: Id36d75b447971e8ab9118ab46c1fa54caaee948d

src/main/java/com/google/devtools/build/lib/runtime/commands/LicenseCommand.java

diff --git a/src/main/java/com/google/devtools/build/lib/runtime/commands/LicenseCommand.java b/src/main/java/com/google/devtools/build/lib/runtime/commands/LicenseCommand.java
index 7ad512a..a7ca2c6 100644
--- a/src/main/java/com/google/devtools/build/lib/runtime/commands/LicenseCommand.java
+++ b/src/main/java/com/google/devtools/build/lib/runtime/commands/LicenseCommand.java
@@ -13,7 +13,7 @@
 // limitations under the License.
 package com.google.devtools.build.lib.runtime.commands;
 
-import com.google.common.io.Files;
+import com.google.common.collect.ImmutableSet;
 import com.google.devtools.build.lib.analysis.NoBuildEvent;
 import com.google.devtools.build.lib.runtime.BlazeCommand;
 import com.google.devtools.build.lib.runtime.BlazeCommandResult;
@@ -22,11 +22,15 @@
 import com.google.devtools.build.lib.util.ExitCode;
 import com.google.devtools.build.lib.util.ResourceFileLoader;
 import com.google.devtools.build.lib.util.io.OutErr;
-import com.google.devtools.build.lib.vfs.Path;
 import com.google.devtools.common.options.OptionsParser;
 import com.google.devtools.common.options.OptionsProvider;
 import java.io.IOException;
-import java.util.TreeSet;
+import java.io.UncheckedIOException;
+import java.nio.file.FileVisitResult;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.SimpleFileVisitor;
+import java.nio.file.attribute.BasicFileAttributes;
 
 /** A command that prints an embedded license text. */
 @Command(
@@ -38,15 +42,8 @@
 )
 public class LicenseCommand implements BlazeCommand {
 
-  private static final TreeSet<String> JAVA_LICENSE_FILES =
-      new TreeSet<>(String.CASE_INSENSITIVE_ORDER);
-
-  static {
-    JAVA_LICENSE_FILES.add("ASSEMBLY_EXCEPTION");
-    JAVA_LICENSE_FILES.add("DISCLAIMER");
-    JAVA_LICENSE_FILES.add("LICENSE");
-    JAVA_LICENSE_FILES.add("THIRD_PARTY_README");
-  }
+  private static final ImmutableSet<String> JAVA_LICENSE_FILES =
+      ImmutableSet.of("ASSEMBLY_EXCEPTION", "DISCLAIMER", "LICENSE", "THIRD_PARTY_README");
 
   public static boolean isSupported() {
     return ResourceFileLoader.resourceExists(LicenseCommand.class, "LICENSE");
@@ -67,16 +64,24 @@
     }
 
     Path bundledJdk =
-        env.getDirectories().getEmbeddedBinariesRoot().getRelative("embedded_tools/jdk");
-    if (bundledJdk.exists()) {
+        env.getDirectories()
+            .getEmbeddedBinariesRoot()
+            .getRelative("embedded_tools/jdk")
+            .getPathFile()
+            .toPath();
+    if (Files.exists(bundledJdk)) {
       outErr.printOutLn(
           "This binary comes with a bundled JDK, which contains the following license files:\n");
       printJavaLicenseFiles(outErr, bundledJdk);
     }
 
     Path bundledJre =
-        env.getDirectories().getEmbeddedBinariesRoot().getRelative("embedded_tools/jre");
-    if (bundledJre.exists()) {
+        env.getDirectories()
+            .getEmbeddedBinariesRoot()
+            .getRelative("embedded_tools/jre")
+            .getPathFile()
+            .toPath();
+    if (Files.exists(bundledJre)) {
       outErr.printOutLn(
           "This binary comes with a bundled JRE, which contains the following license files:\n");
       printJavaLicenseFiles(outErr, bundledJre);
@@ -87,15 +92,22 @@
 
   private static void printJavaLicenseFiles(OutErr outErr, Path bundledJdkOrJre) {
     try {
-      for (Path path : bundledJdkOrJre.getDirectoryEntries()) {
-        if (JAVA_LICENSE_FILES.contains(path.getBaseName().toLowerCase())) {
-          outErr.printOutLn(path.getPathString() + ":\n");
-          Files.copy(path.getPathFile(), outErr.getOutputStream());
-          outErr.printOutLn("\n");
-        }
-      }
+      Files.walkFileTree(
+          bundledJdkOrJre,
+          new SimpleFileVisitor<Path>() {
+            @Override
+            public FileVisitResult visitFile(Path path, BasicFileAttributes basicFileAttributes)
+                throws IOException {
+              if (JAVA_LICENSE_FILES.contains(path.getFileName().toString())) {
+                outErr.printOutLn(path + ":\n");
+                Files.copy(path, outErr.getOutputStream());
+                outErr.printOutLn("\n");
+              }
+              return super.visitFile(path, basicFileAttributes);
+            }
+          });
     } catch (IOException e) {
-      throw new IllegalStateException(
+      throw new UncheckedIOException(
           "I/O error while trying to print license file of bundled JDK or JRE: " + e.getMessage(),
           e);
     }