diff --git a/dev-java/jamvm/files/jamvm-1.5.4-classes-location.patch b/dev-java/jamvm/files/jamvm-1.5.4-classes-location.patch
new file mode 100644
index 0000000000000..57d046a81882a
--- /dev/null
+++ b/dev-java/jamvm/files/jamvm-1.5.4-classes-location.patch
@@ -0,0 +1,27 @@
+diff -ur jamvm-1.5.0.old/configure.ac jamvm-1.5.0/configure.ac
+--- jamvm-1.5.0.old/configure.ac	2008-03-03 17:31:46.000000000 +0200
++++ jamvm-1.5.0/configure.ac	2008-03-03 17:36:14.000000000 +0200
+@@ -208,6 +208,7 @@
+     install_dir=$prefix
+ fi
+ AC_DEFINE_UNQUOTED(INSTALL_DIR, "$install_dir", [Installation directory (prefix)])
++AC_DEFINE_UNQUOTED(PKGDATADIR, "$datadir/$PACKAGE", [Package data directory (pkgdatadir)])
+ 
+ AC_ARG_ENABLE(zip,
+     [AS_HELP_STRING(--disable-zip,turn-off zip support in the bootstrap loader)],,)
+diff -ur jamvm-1.5.0.old/src/class.h jamvm-1.5.0/src/class.h
+--- jamvm-1.5.0.old/src/class.h	2008-03-03 17:31:46.000000000 +0200
++++ jamvm-1.5.0/src/class.h	2008-03-03 17:36:51.000000000 +0200
+@@ -39,10 +39,10 @@
+    separate class files in a directory structure */
+ 
+ #ifdef USE_ZIP
+-#define JAMVM_CLASSES INSTALL_DIR"/share/jamvm/classes.zip"
++#define JAMVM_CLASSES PKGDATADIR"/classes.zip"
+ #define CLASSPATH_CLASSES CLASSPATH_INSTALL_DIR"/share/classpath/glibj.zip"
+ #else
+-#define JAMVM_CLASSES INSTALL_DIR"/share/jamvm/classes"
++#define JAMVM_CLASSES PKGDATADIR"/classes"
+ #define CLASSPATH_CLASSES CLASSPATH_INSTALL_DIR"/share/classpath"
+ #endif
+ 
diff --git a/dev-java/jamvm/files/jamvm-1.5.4-r2.env b/dev-java/jamvm/files/jamvm-1.5.4-env.file
similarity index 100%
rename from dev-java/jamvm/files/jamvm-1.5.4-r2.env
rename to dev-java/jamvm/files/jamvm-1.5.4-env.file
diff --git a/dev-java/jamvm/files/classes-location.patch b/dev-java/jamvm/files/jamvm-2.0.0-classes-location.patch
similarity index 100%
rename from dev-java/jamvm/files/classes-location.patch
rename to dev-java/jamvm/files/jamvm-2.0.0-classes-location.patch
diff --git a/dev-java/jamvm/files/jamvm.env b/dev-java/jamvm/files/jamvm-2.0.0-env.file
similarity index 100%
rename from dev-java/jamvm/files/jamvm.env
rename to dev-java/jamvm/files/jamvm-2.0.0-env.file
diff --git a/dev-java/jamvm/files/javac.in b/dev-java/jamvm/files/jamvm-2.0.0-javac.in
similarity index 100%
rename from dev-java/jamvm/files/javac.in
rename to dev-java/jamvm/files/jamvm-2.0.0-javac.in
diff --git a/dev-java/jamvm/files/noexecstack.patch b/dev-java/jamvm/files/jamvm-2.0.0-noexecstack.patch
similarity index 100%
rename from dev-java/jamvm/files/noexecstack.patch
rename to dev-java/jamvm/files/jamvm-2.0.0-noexecstack.patch
diff --git a/dev-java/jamvm/jamvm-1.5.4-r2.ebuild b/dev-java/jamvm/jamvm-1.5.4-r2.ebuild
index 163773a18ea91..03dccea6ed94d 100644
--- a/dev-java/jamvm/jamvm-1.5.4-r2.ebuild
+++ b/dev-java/jamvm/jamvm-1.5.4-r2.ebuild
@@ -21,9 +21,13 @@ DEPEND="dev-java/gnu-classpath:${CLASSPATH_SLOT}
 	amd64? ( virtual/libffi )"
 RDEPEND="${DEPEND}"
 
+PATCHES=(
+	"${FILESDIR}"/"${P}-classes-location.patch"
+)
+
 src_prepare() {
 	# without this patch, classes.zip is not found at runtime
-	epatch "${FILESDIR}/classes-location.patch"
+	epatch "${PATCHES[@]}"
 	eautoreconf
 
 	# These come precompiled.
@@ -76,7 +80,7 @@ src_install() {
 
 	dodoc ACKNOWLEDGEMENTS AUTHORS ChangeLog NEWS README
 
-	set_java_env "${FILESDIR}/${PN}-1.5.4-r2.env"
+	set_java_env "${FILESDIR}/${P}-env.file"
 
 	dosym /usr/bin/jamvm ${INSTALL_DIR}/bin/java
 	dosym ${CLASSPATH_DIR}/share/classpath/glibj.zip ${INSTALL_DIR}/jre/lib/rt.jar
diff --git a/dev-java/jamvm/jamvm-2.0.0-r1.ebuild b/dev-java/jamvm/jamvm-2.0.0-r1.ebuild
index 65eeb618fa67e..878fd1b711eec 100644
--- a/dev-java/jamvm/jamvm-2.0.0-r1.ebuild
+++ b/dev-java/jamvm/jamvm-2.0.0-r1.ebuild
@@ -22,10 +22,14 @@ DEPEND="dev-java/gnu-classpath:0.98
 	sparc? ( virtual/libffi )"
 RDEPEND="${DEPEND}"
 
+PATCHES=(
+	"${FILESDIR}"/"${P}-classes-location.patch"
+	"${FILESDIR}"/"${P}-noexecstack.patch"
+)
+
 src_prepare() {
 	# without this patch, classes.zip is not found at runtime
-	epatch "${FILESDIR}/classes-location.patch"
-	epatch "${FILESDIR}/noexecstack.patch"
+	epatch "${PATCHES[@]}"
 	eautoreconf
 
 	# These come precompiled.
@@ -65,7 +69,7 @@ create_launcher() {
 			-Xbootclasspath/p:/usr/share/classpath/tools.zip" \
 			gnu.classpath.tools.${1}.Main "\$@"
 	EOF
-	chmod +x "${script}"
+	chmod +x "${script}" || die
 }
 
 src_install() {
@@ -77,7 +81,7 @@ src_install() {
 
 	dodoc ACKNOWLEDGEMENTS AUTHORS ChangeLog NEWS README
 
-	set_java_env "${FILESDIR}/${PN}.env"
+	set_java_env "${FILESDIR}/${P}-env.file"
 
 	dodir ${JDK_DIR}/bin
 	dosym /usr/bin/jamvm ${JDK_DIR}/bin/java
@@ -97,11 +101,11 @@ src_install() {
 
 	local ecj_jar="$(readlink "${EPREFIX}"/usr/share/eclipse-ecj/ecj.jar)"
 	exeinto ${JDK_DIR}/bin
-	cat "${FILESDIR}"/javac.in | sed -e "s#@JAVA@#/usr/bin/jamvm#" \
+	sed -e "s#@JAVA@#/usr/bin/jamvm#" \
 		-e "s#@ECJ_JAR@#${ecj_jar}#" \
 		-e "s#@RT_JAR@#/usr/share/classpath/glibj.zip#" \
 		-e "s#@TOOLS_JAR@#/usr/share/classpath/tools.zip#" \
-	| newexe - javac
+		"${FILESDIR}"/"${P}-javac.in" | newexe - javac
 
 	local libarch="${ARCH}"
 	[ ${ARCH} == x86 ] && libarch="i386"