src/jdk.jlink/share/classes/jdk/tools/jlink/internal/Jlink.java

*** 25,35 ****
--- 25,37 ----
  package jdk.tools.jlink.internal;
  
  import java.lang.module.Configuration;
  import java.lang.module.ModuleFinder;
  import java.nio.ByteOrder;
+ import java.nio.file.Files;
  import java.nio.file.Path;
+ import java.nio.file.Paths;
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.List;
  import java.util.Map;
  import java.util.Objects;
*** 174,184 ****
              this.output = output;
              this.modulepaths = modulepaths;
              this.modules = Objects.requireNonNull(modules);
              this.limitmods = Objects.requireNonNull(limitmods);
              this.endian = Objects.requireNonNull(endian);
!             this.finder = moduleFinder();
          }
  
          /**
           * @return the modulepaths
           */
--- 176,203 ----
              this.output = output;
              this.modulepaths = modulepaths;
              this.modules = Objects.requireNonNull(modules);
              this.limitmods = Objects.requireNonNull(limitmods);
              this.endian = Objects.requireNonNull(endian);
!             ModuleFinder finder = moduleFinder(modulepaths, limitmods, modules);
!             if (! finder.find("java.base").isPresent()) {
!                 Path sysPath = getDefaultModulePath();
!                 if (sysPath != null) {
!                     this.modulepaths.add(sysPath);
!                 }
!                 // if java.base is still not found, error will be thrown later!
!                 finder = moduleFinder(modulepaths, limitmods, modules);
!             }
!             this.finder = finder;
!         }
! 
!         /**
!          * @return the system module path or null
!          */
!         public static Path getDefaultModulePath() {
!             Path jmods = Paths.get(System.getProperty("java.home"), "jmods");
!             return Files.isDirectory(jmods)? jmods : null;
          }
  
          /**
           * @return the modulepaths
           */
*** 242,252 ****
              return Configuration.empty().resolve(finder,
                                                   ModuleFinder.of(),
                                                   modules);
          }
  
!         private ModuleFinder moduleFinder() {
              Path[] entries = modulepaths.toArray(new Path[0]);
              ModuleFinder finder = ModulePath.of(Runtime.version(), true, entries);
              if (!limitmods.isEmpty()) {
                  finder = JlinkTask.limitFinder(finder, limitmods, modules);
              }
--- 261,272 ----
              return Configuration.empty().resolve(finder,
                                                   ModuleFinder.of(),
                                                   modules);
          }
  
!         private static ModuleFinder moduleFinder(List<Path> modulepaths,
!                 Set<String> limitmods, Set<String> modules) {
              Path[] entries = modulepaths.toArray(new Path[0]);
              ModuleFinder finder = ModulePath.of(Runtime.version(), true, entries);
              if (!limitmods.isEmpty()) {
                  finder = JlinkTask.limitFinder(finder, limitmods, modules);
              }