diff --git a/gnu/packages/java.scm b/gnu/packages/java.scm
index 403c446a82..0245b299f8 100644
--- a/gnu/packages/java.scm
+++ b/gnu/packages/java.scm
@@ -116,6 +116,8 @@
                (base32
                 "1qqldrp74pzpy5ly421srqn30qppmm9cvjiqdngk8hf47dv2rc0c"))))
     (build-system gnu-build-system)
+    (native-inputs
+     `(("gcc" ,gcc-5)))
     (home-page "http://jikes.sourceforge.net/")
     (synopsis "Compiler for the Java language")
     (description "Jikes is a compiler that translates Java source files as
@@ -152,13 +154,43 @@ and binary format defined in The Java Virtual Machine Specification.")
              "--disable-gjdoc")
        #:phases
        (modify-phases %standard-phases
+         (add-after 'unpack 'foo
+           (lambda _
+             (substitute* "native/jni/native-lib/cpio.c"
+               (("\\(stat\\(filename, &statbuf\\) < 0\\)")
+                "(stat(filename, &statbuf) != 0)"))
+             (substitute* "native/jni/java-io/java_io_VMFile.c"
+               (("return result == CPNATIVE_OK \\? 1 : 0;")
+                "return ((result == CPNATIVE_OK) ? 1 : 0);")
+               (("result = cpio_isFileExists.*" m)
+                (string-append m "\nfprintf(stderr, \"exists? %s : %d -- %d;\\n\", filename, result, ((result == CPNATIVE_OK) ? 1 : 0));")))
+             (substitute* "java/io/File.java"
+               (("String filename = ") "filename =")
+               (("File file;" m)
+                (string-append m "\nString filename;"))
+
+               ;; (("while \\(VMFile.exists\\(file.path\\)\\)")
+               ;;  "while (false)")
+               (("while \\(VMFile.exists\\(file.path\\)\\)")
+                "while (VMFile.exists(directory.path + \"/\" + filename))")
+               (("// Grab the system" m)
+                (string-append "System.err.println(\"classpath called createTempFile: prefix \" + prefix + \" suffix \" + suffix + \" directory \" + directory.path );\n"
+                               m))
+               (("// Verify that we" m)
+                (string-append "System.err.println(\"classpath after loop with: \" + prefix);\n
+file = new File(directory, filename);"
+                               m))
+               (("file = new File.*" m)
+                (string-append m "\nSystem.err.println(\"classpath trying to create: \" + file.path + \" exists? \" + String.valueOf(VMFile.exists(file.path)));\n")))
+             #t))
          (add-after 'install 'install-data
            (lambda _ (invoke "make" "install-data"))))))
     (native-inputs
      `(("jikes" ,jikes)
        ("fastjar" ,fastjar)
        ("libltdl" ,libltdl)
-       ("pkg-config" ,pkg-config)))
+       ("pkg-config" ,pkg-config)
+       ("gcc" ,gcc-5)))
     (home-page "https://www.gnu.org/software/classpath/")
     (synopsis "Essential libraries for Java")
     (description "GNU Classpath is a project to create core class libraries
@@ -191,6 +223,8 @@ language.")
      `(("classpath" ,classpath-bootstrap)
        ("jikes" ,jikes)
        ("zlib" ,zlib)))
+    (native-inputs
+     `(("gcc-5" ,gcc-5)))
     (home-page "http://jamvm.sourceforge.net/")
     (synopsis "Small Java Virtual Machine")
     (description "JamVM is a Java Virtual Machine conforming to the JVM
@@ -225,7 +259,6 @@ JNI.")
        #:tests? #f ; no "check" target
        #:phases
        (modify-phases %standard-phases
-         (delete 'bootstrap)
          (delete 'configure)
          (replace 'build
            (lambda* (#:key inputs #:allow-other-keys)
@@ -244,9 +277,12 @@ JNI.")
              (setenv "HOME" "/tmp")
              (with-output-to-file "/tmp/.ant.properties"
                (lambda _ (display "")))
+             (with-output-to-file ".ant.properties"
+               (lambda _ (display "")))
 
              ;; Use jikes instead of javac for <javac ...> tags in build.xml
-             (setenv "ANT_OPTS" "-Dbuild.compiler=jikes")
+             (setenv "ANT_OPTS"
+                     "-Dbuild.compiler=jikes -Djava.io.tmpdir=/tmp")
 
              ;; jikes produces lots of warnings, but they are not very
              ;; interesting, so we silence them.
@@ -254,15 +290,49 @@ JNI.")
 
              ;; Without these JamVM options the build may freeze.
              (substitute* "bootstrap.sh"
+               ;;(("-emacs") "-debug")
                (("^\"\\$\\{JAVACMD\\}\" " m)
                 ,@(if (string-prefix? "armhf" (or (%current-system)
                                                   (%current-target-system)))
                       `((string-append m "-Xnocompact "))
                       `((string-append m "-Xnocompact -Xnoinlining ")))))
 
+             (substitute* "src/main/org/apache/tools/ant/version.txt"
+               (("VERSION=.*") (string-append "VERSION=" ,version "\n"))
+               (("DATE=.*") "DATE=reproducible"))
+
+             ;; XXX: Copying the source files appears to be necessary because
+             ;; ant won't find the XML and txt resources in src/main for some
+             ;; reason.  It really shouldn't be needed, so maybe this can be
+             ;; avoided by setting some environment variable.
+             (substitute* "bootstrap.sh"
+               (("cp src/script/antRun bin" m)
+                (string-append m "
+cp -ar {src/main,build/classes}/org/apache/tools/ant/version.txt
+cp -ar {src/main,build/classes}/org/apache/tools/ant/antlib.xml
+")))
+             (substitute* "src/main/org/apache/tools/ant/taskdefs/compilers/DefaultCompilerAdapter.java"
+               (("tmpFile = FILE_UTILS.createTempFile" m)
+                (string-append "attributes.log(\"REKADO createTempFile\", Project.MSG_WARN);"
+                               m))
+               (("out = new.*" m)
+                (string-append m
+                               "\nattributes.log(\"REKADO created\", Project.MSG_WARN);"))
+               (("exe.execute\\(\\)" m)
+                (string-append "attributes.log(\"REKADO executing\", Project.MSG_WARN);"
+                               m)))
+
+             (substitute* "src/main/org/apache/tools/ant/util/FileUtils.java"
+               (("result = File.*" m)
+                (string-append "System.err.println(\"Trying to create \" + prefix);\n"
+                               m
+                               "\nSystem.err.println(\"Created file \" + result);")))
+             
              ;; Disable tests because we are bootstrapping and thus don't have
              ;; any of the dependencies required to build and run the tests.
              (substitute* "build.xml"
+               ;; (("includeantruntime=\"false\"")
+               ;;  (string-append "includeantruntime=\"true\" createMissingPackageInfoClass=\"false\" fork=\"true\""))
                (("depends=\"jars,test-jar\"") "depends=\"jars\""))
              (invoke "bash" "bootstrap.sh"
                      (string-append "-Ddist.dir="