There was some code in configure.ac dating back to 2009 (commit b9014d6a0da8b2b3a76c4ab51fab2773fe7480b2) which attempted to add the javac option `-source 1.5'. I don't think this code ever worked. However, if -source 1.5 is added, then you get this warning: warning: [options] bootstrap class path not set in conjunction with -source 1.5 warning: [options] source value 1.5 is obsolete and will be removed in a future release warning: [options] To suppress warnings about obsolete options, use -Xlint:-options. and that's very hard to reliably fix because you have to know somehow a magic path. For more details, see: https://blogs.oracle.com/darcy/entry/bootclasspath_older_source https://blogs.oracle.com/darcy/entry/how_to_cross_compile_for Anyway, remove the voodoo from configure.ac. As a side effect, this allows you to set the EXTRA_JAVAC_FLAGS environment variable before ./configure with any extra javac flags that you want. --- m4/guestfs_java.m4 | 10 ---------- 1 file changed, 10 deletions(-) diff --git a/m4/guestfs_java.m4 b/m4/guestfs_java.m4 index 649e21f..82cdc40 100644 --- a/m4/guestfs_java.m4 +++ b/m4/guestfs_java.m4 @@ -123,16 +123,6 @@ if test "x$with_java" != "xno"; then fi AC_MSG_RESULT([$JNI_CFLAGS]) - dnl Need extra version flag? - AC_MSG_CHECKING([extra javac flags]) - EXTRA_JAVAC_FLAGS= - javac_version=`$JAVAC -version 2>&1` - case "$javac_version" in - *Eclipse*) - EXTRA_JAVAC_FLAGS="-source 1.5" ;; - esac - AC_MSG_RESULT([$EXTRA_JAVAC_FLAGS]) - dnl Extra lint flags? AC_MSG_CHECKING([extra javac lint flags]) if $JAVAC -X >/dev/null 2>&1 && \ -- 2.7.4