diff --git a/aclocal.m4 b/aclocal.m4
index 4fc4d0c1a..27fa77c05 100644
--- a/aclocal.m4
+++ b/aclocal.m4
@@ -328,7 +328,7 @@ if test "$JAVAC" != "" -a "$JAVA_INTERPRETER" != "" -a "$JAR" != ""; then
 	cat > conftest.java << EOF
 		// This program simply retrieves the constant
 		// specifying the version number of the Java SDK and
-		// checks it is at least 1.2, printing "Hello, world"
+		// checks it is at least 1.5, printing "Hello, world"
 		// if successful.
 		public class conftest {
 		    public static void main (String[[]] args) {
@@ -348,7 +348,7 @@ if test "$JAVAC" != "" -a "$JAVA_INTERPRETER" != "" -a "$JAR" != ""; then
 				version = 0f;
 			}
 
-			if (version >= 1.2f) {
+			if (version >= 1.5f) {
 				System.out.println("Hello, world\n");
 			} else {
 				System.out.println("Nope, sorry.\n");
@@ -387,6 +387,29 @@ AC_SUBST(JAVA_INTERPRETER)
 AC_SUBST(JAR)
 ])
 
+AC_DEFUN(MERCURY_CHECK_JAVAC_HEAP_SIZE,
+[
+# The default maximum heap size is too small to build the standard library and
+# other programs so we need to increase it.  The option to do that is
+# non-standard so we have to check that it is accepted.
+AC_CACHE_VAL(mercury_cv_javac_flags_for_heap_size, [
+if test "$mercury_cv_java" = "yes"; then
+	AC_MSG_CHECKING(if the Java compiler accepts the max heap size option)
+	mercury_cv_javac_flags_for_heap_size="-J-Xmx256m"
+	if "$JAVAC" "$mercury_cv_javac_flags_for_heap_size" -version \
+                2> /dev/null
+        then
+		AC_MSG_RESULT(yes)
+	else
+		AC_MSG_RESULT(no)
+		mercury_cv_javac_flags_for_heap_size=
+	fi
+else
+	mercury_cv_javac_flags_for_heap_size=
+fi
+])
+])
+
 #-----------------------------------------------------------------------------#
 #
 # Erlang configuration
diff --git a/configure.in b/configure.in
index 0b1e993cc..fd5090ef9 100644
--- a/configure.in
+++ b/configure.in
@@ -1051,6 +1051,23 @@ MERCURY_CHECK_DOTNET
 
 MERCURY_CHECK_JAVA
 
+AC_ARG_ENABLE(javac-flags-for-heap-size,
+    AC_HELP_STRING([--enable-javac-flags-for-heap-size],
+                   [enable maximum heap size option for Java compiler]),
+    enable_javac_flags_for_heap_size="$enableval",
+    enable_javac_flags_for_heap_size=yes)
+
+case "$enable_javac_flags_for_heap_size" in
+    yes)
+        MERCURY_CHECK_JAVAC_HEAP_SIZE
+        JAVAC_FLAGS_FOR_HEAP_SIZE=$mercury_cv_javac_flags_for_heap_size
+        ;;
+    no)
+        JAVAC_FLAGS_FOR_HEAP_SIZE=
+        ;;
+esac
+AC_SUBST(JAVAC_FLAGS_FOR_HEAP_SIZE)
+
 #-----------------------------------------------------------------------------#
 # Erlang configuration
 #
@@ -3170,14 +3187,13 @@ AC_ARG_ENABLE(dotnet-grades,
     AC_HELP_STRING([--enable-dotnet-grades], [install the .NET grades]),
     enable_dotnet_grades="$enableval",enable_dotnet_grades=no)
 
-# XXX The java backend is currently broken, so we don't
-# enable the java grade by default.
+# We don't enable the java grade by default.
 AC_ARG_ENABLE(java-grade,
    AC_HELP_STRING([--enable-java-grade], [install the Java grade]),
    enable_java_grade="$enableval",enable_java_grade=no)
 
 # We don't enable the Erlang grades by default because it is still
-# experimental and it requires mmc --make to install.
+# experimental.
 AC_ARG_ENABLE(erlang-grade,
    AC_HELP_STRING([--enable-erlang-grade], [install the Erlang grade]),
    enable_erlang_grade="$enableval",enable_erlang_grade=no)
diff --git a/scripts/Mercury.config.bootstrap.in b/scripts/Mercury.config.bootstrap.in
index fbbf8c122..b8c91646c 100644
--- a/scripts/Mercury.config.bootstrap.in
+++ b/scripts/Mercury.config.bootstrap.in
@@ -63,6 +63,7 @@ DEFAULT_MCFLAGS=\
 		--c-flag-to-name-object-file "@OBJFILE_OPT@" \
 		--java-classpath "$(INSTALL_JAVA_LIBRARY_DIR)/$(RT_LIB_NAME).jar" \
 		--java-classpath "$(INSTALL_JAVA_LIBRARY_DIR)/$(STD_LIB_NAME).jar" \
+		--java-flags "@JAVAC_FLAGS_FOR_HEAP_SIZE@" \
 		--object-file-extension ".@OBJ_SUFFIX@" \
 		--pic-object-file-extension ".@EXT_FOR_PIC_OBJECTS@" \
 		--link-with-pic-object-file-extension ".@EXT_FOR_LINK_WITH_PIC_OBJECTS@" \
diff --git a/scripts/Mercury.config.in b/scripts/Mercury.config.in
index 0a7204af0..b2df88bde 100644
--- a/scripts/Mercury.config.in
+++ b/scripts/Mercury.config.in
@@ -69,6 +69,7 @@ DEFAULT_MCFLAGS=\
 		--c-flag-to-name-object-file "@OBJFILE_OPT@" \
 		--java-classpath "$(INSTALL_JAVA_LIBRARY_DIR)/$(RT_LIB_NAME).jar" \
 		--java-classpath "$(INSTALL_JAVA_LIBRARY_DIR)/$(STD_LIB_NAME).jar" \
+		--java-flags "@JAVAC_FLAGS_FOR_HEAP_SIZE@" \
 		--object-file-extension ".@OBJ_SUFFIX@" \
 		--pic-object-file-extension ".@EXT_FOR_PIC_OBJECTS@" \
 		--link-with-pic-object-file-extension ".@EXT_FOR_LINK_WITH_PIC_OBJECTS@" \
diff --git a/scripts/Mmake.vars.in b/scripts/Mmake.vars.in
index 03fe22720..4922837f9 100644
--- a/scripts/Mmake.vars.in
+++ b/scripts/Mmake.vars.in
@@ -268,7 +268,7 @@ LIB_MS_CSCFLAGS	=
 JAVAC		= @JAVAC@
 ALL_JAVACFLAGS	= $(JAVACFLAGS) $(EXTRA_JAVACFLAGS) $(TARGET_JAVACFLAGS) \
 		$(LIB_JAVACFLAGS)
-JAVACFLAGS	=
+JAVACFLAGS	= @JAVAC_FLAGS_FOR_HEAP_SIZE@
 EXTRA_JAVACFLAGS =
 # XXX Should we set LIB_JAVACFLAGS?
 LIB_JAVACFLAGS	=