diff --git a/bin/ruby-build b/bin/ruby-build
index c2b8c0e4..87ce35c8 100755
--- a/bin/ruby-build
+++ b/bin/ruby-build
@@ -798,15 +798,21 @@ fix_rbx_irb() {
     true
 }
 
-require_java7() {
-  local version="$(java -version 2>&1 | grep '\(java\|openjdk\) version' | head -1)"
-  if [[ $version != *[789]* ]]; then
+require_java() {
+  local required="$1"
+  local version="$(java -version 2>&1 | grep '\(java\|openjdk\) version' | head -1 | grep -o '1\.[0-9]\+')"
+  if [ -z "$version" ] || [ "${version##*.}" -lt "$required" ]; then
     colorize 1 "ERROR" >&3
-    echo ": Java 7 required. Please install a 1.7-compatible JRE." >&3
+    echo ": Java ${required} required. Please install a 1.${required}-compatible JRE." >&3
     return 1
   fi
 }
 
+# keep for backwards compatibility
+require_java7() {
+  require_java 7
+}
+
 require_gcc() {
   local gcc="$(locate_gcc || true)"
 
diff --git a/share/ruby-build/jruby-9.2.0.0 b/share/ruby-build/jruby-9.2.0.0
index 03868d20..121af2c7 100644
--- a/share/ruby-build/jruby-9.2.0.0
+++ b/share/ruby-build/jruby-9.2.0.0
@@ -1,2 +1,2 @@
-require_java8
+require_java 8
 install_package "jruby-9.2.0.0" "https://s3.amazonaws.com/jruby.org/downloads/9.2.0.0/jruby-bin-9.2.0.0.tar.gz#42718dea5fc90b7696cb3fccf8e8d546729173963ad0bc477d66545677d00684" jruby
diff --git a/share/ruby-build/jruby-9.2.0.0-dev b/share/ruby-build/jruby-9.2.0.0-dev
index 8bb1c200..81bc6f05 100644
--- a/share/ruby-build/jruby-9.2.0.0-dev
+++ b/share/ruby-build/jruby-9.2.0.0-dev
@@ -1,2 +1,2 @@
-require_java8
+require_java 8
 install_package "jruby-9.2.0.0-SNAPSHOT" "https://projectodd.ci.cloudbees.com/view/JRuby/job/jruby-development-dist/lastSuccessfulBuild/artifact/release/jruby-bin-9.2.0.0-SNAPSHOT.tar.gz" jruby
diff --git a/share/ruby-build/jruby-9.2.1.0 b/share/ruby-build/jruby-9.2.1.0
index c13835f4..e396feae 100644
--- a/share/ruby-build/jruby-9.2.1.0
+++ b/share/ruby-build/jruby-9.2.1.0
@@ -1,2 +1,2 @@
-require_java8
+require_java 8
 install_package "jruby-9.2.1.0" "https://repo1.maven.org/maven2/org/jruby/jruby-dist/9.2.1.0/jruby-dist-9.2.1.0-bin.tar.gz#8c987378b144eff0dcc553312f1853c05ee9135f3ffdac7b0828b7ad62f32835" jruby
diff --git a/share/ruby-build/jruby-9.2.1.0-dev b/share/ruby-build/jruby-9.2.1.0-dev
index 81898a01..d1a90d4e 100644
--- a/share/ruby-build/jruby-9.2.1.0-dev
+++ b/share/ruby-build/jruby-9.2.1.0-dev
@@ -1,2 +1,2 @@
-require_java8
+require_java 8
 install_package "jruby-9.2.1.0-SNAPSHOT" "https://projectodd.ci.cloudbees.com/view/JRuby/job/jruby-development-dist/lastSuccessfulBuild/artifact/release/jruby-bin-9.2.1.0-SNAPSHOT.tar.gz" jruby
diff --git a/share/ruby-build/jruby-9.2.3.0 b/share/ruby-build/jruby-9.2.3.0
index b6311c89..3680de72 100644
--- a/share/ruby-build/jruby-9.2.3.0
+++ b/share/ruby-build/jruby-9.2.3.0
@@ -1,2 +1,2 @@
-require_java8
+require_java 8
 install_package "jruby-9.2.3.0" "https://s3.amazonaws.com/jruby.org/downloads/9.2.3.0/jruby-bin-9.2.3.0.tar.gz#d9c2d179696394aafe41027f0e48fa53267ecde04b3d10babc88fea4d523336a" jruby
diff --git a/share/ruby-build/jruby-9.2.4.0 b/share/ruby-build/jruby-9.2.4.0
index 0ac3a280..f65b54a9 100644
--- a/share/ruby-build/jruby-9.2.4.0
+++ b/share/ruby-build/jruby-9.2.4.0
@@ -1,2 +1,2 @@
-require_java8
+require_java 8
 install_package "jruby-9.2.4.0" "https://s3.amazonaws.com/jruby.org/downloads/9.2.4.0/jruby-bin-9.2.4.0.tar.gz#b9638c82c85d89f6e8b2da1b876ac235bb9ed47f2163b3c851f0496c9bd58a0c" jruby
diff --git a/share/ruby-build/jruby-9.2.4.1 b/share/ruby-build/jruby-9.2.4.1
index 7eeaeb02..6f45b645 100644
--- a/share/ruby-build/jruby-9.2.4.1
+++ b/share/ruby-build/jruby-9.2.4.1
@@ -1,2 +1,2 @@
-require_java8
+require_java 8
 install_package "jruby-9.2.4.1" "https://s3.amazonaws.com/jruby.org/downloads/9.2.4.1/jruby-bin-9.2.4.1.tar.gz#c89821120d74f17f90c9bc346cc7bd1278df623fc1fe60ea3b5c0a8a01360d5b" jruby
diff --git a/share/ruby-build/jruby-9.2.5.0 b/share/ruby-build/jruby-9.2.5.0
index 6082dbab..8e484239 100644
--- a/share/ruby-build/jruby-9.2.5.0
+++ b/share/ruby-build/jruby-9.2.5.0
@@ -1,2 +1,2 @@
-require_java8
+require_java 8
 install_package "jruby-9.2.5.0" "https://s3.amazonaws.com/jruby.org/downloads/9.2.5.0/jruby-bin-9.2.5.0.tar.gz#f4ad088082eca73561df983f6cb0a937b966cba3a36454e88f63930ed2bdf349" jruby
diff --git a/share/ruby-build/jruby-9.2.6.0 b/share/ruby-build/jruby-9.2.6.0
index a7a2d6cd..c0aa5e07 100644
--- a/share/ruby-build/jruby-9.2.6.0
+++ b/share/ruby-build/jruby-9.2.6.0
@@ -1,2 +1,2 @@
-require_java8
+require_java 8
 install_package "jruby-9.2.6.0" "https://s3.amazonaws.com/jruby.org/downloads/9.2.6.0/jruby-bin-9.2.6.0.tar.gz#70a1ff0e17a98baa63ea92c91fd38ff1e55a2056e5d57ba0409c4543d29e0e3d" jruby
diff --git a/share/ruby-build/jruby-9.2.7.0 b/share/ruby-build/jruby-9.2.7.0
index 8f85ae53..f7384ad9 100644
--- a/share/ruby-build/jruby-9.2.7.0
+++ b/share/ruby-build/jruby-9.2.7.0
@@ -1,2 +1,2 @@
-require_java8
+require_java 8
 install_package "jruby-9.2.7.0" "https://s3.amazonaws.com/jruby.org/downloads/9.2.7.0/jruby-bin-9.2.7.0.tar.gz#da7c1a5ce90015c0bafd4bca0352294e08fe1c9ec049ac51e82fe57ed50e1348" jruby
diff --git a/share/ruby-build/jruby-9.2.8.0 b/share/ruby-build/jruby-9.2.8.0
index e0450851..373e0e08 100644
--- a/share/ruby-build/jruby-9.2.8.0
+++ b/share/ruby-build/jruby-9.2.8.0
@@ -1,2 +1,2 @@
-require_java8
+require_java 8
 install_package "jruby-9.2.8.0" "https://s3.amazonaws.com/jruby.org/downloads/9.2.8.0/jruby-bin-9.2.8.0.tar.gz#b7c58688093f54acd89d732a8bf40e3ae0ac4c92488d6f5b424c33e4fb09c7bb" jruby
diff --git a/share/ruby-build/jruby-9.2.9.0 b/share/ruby-build/jruby-9.2.9.0
index 8d1eea6c..8c048e64 100644
--- a/share/ruby-build/jruby-9.2.9.0
+++ b/share/ruby-build/jruby-9.2.9.0
@@ -1,2 +1,2 @@
-require_java8
+require_java 8
 install_package "jruby-9.2.9.0" "https://s3.amazonaws.com/jruby.org/downloads/9.2.9.0/jruby-bin-9.2.9.0.tar.gz#ced3fbb81b4f29f6a7fe7207e678e4154d95cc94de9f509fcaaf05768a6bf911" jruby