diff --git a/src/main/scala/sbtghactions/GenerativePlugin.scala b/src/main/scala/sbtghactions/GenerativePlugin.scala
index 4c9fa78..f1e6aad 100644
--- a/src/main/scala/sbtghactions/GenerativePlugin.scala
+++ b/src/main/scala/sbtghactions/GenerativePlugin.scala
@@ -80,8 +80,13 @@ object GenerativePlugin extends AutoPlugin {
     else
       s"'${str.replace("'", "''")}'"
 
-  def compileList(items: List[String]): String =
-    items.map(wrap).map("- " + _).mkString("\n")
+  def compileList(items: List[String], level: Int): String = {
+    val rendered = items.map(wrap)
+    if (rendered.map(_.length).sum < 40)   // just arbitrarily...
+      rendered.mkString(" [", ", ", "]")
+    else
+      "\n" + indent(rendered.map("- " + _).mkString("\n"), level)
+  }
 
   def compilePREventType(tpe: PREventType): String = {
     import PREventType._
@@ -220,9 +225,9 @@ ${indent(rendered.mkString("\n"), 1)}"""
     val body = s"""name: ${wrap(job.name)}${renderedNeeds}${renderedCond}
 strategy:
   matrix:
-    os: [${job.oses.mkString(", ")}]
-    scala: [${job.scalas.mkString(", ")}]
-    java: [${job.javas.mkString(", ")}]${renderedMatrices}
+    os:${compileList(job.oses, 3)}
+    scala:${compileList(job.scalas, 3)}
+    java:${compileList(job.javas, 3)}${renderedMatrices}
 runs-on: $${{ matrix.os }}${renderedEnv}
 steps:
 ${indent(job.steps.map(compileStep(_, sbt, declareShell = declareShell)).mkString("\n\n"), 1)}"""
diff --git a/src/test/scala/sbtghactions/GenerativePluginSpec.scala b/src/test/scala/sbtghactions/GenerativePluginSpec.scala
index f13894d..b935918 100644
--- a/src/test/scala/sbtghactions/GenerativePluginSpec.scala
+++ b/src/test/scala/sbtghactions/GenerativePluginSpec.scala
@@ -370,6 +370,70 @@ class GenerativePluginSpec extends Specification {
     - name: Checkout current branch (fast)
       uses: actions/checkout@v2"""
     }
+
+    "compile a job with illegal characters in the JVM" in {
+      val results = compileJob(
+        WorkflowJob(
+          "bippy",
+          "Bippity Bop Around the Clock",
+          List(
+            WorkflowStep.Run(List("echo hello")),
+            WorkflowStep.Checkout),
+          javas = List("this:is>#illegal")),
+        "")
+
+      results mustEqual s"""bippy:
+  name: Bippity Bop Around the Clock
+  strategy:
+    matrix:
+      os: [ubuntu-latest]
+      scala: [2.13.1]
+      java: ['this:is>#illegal']
+  runs-on: $${{ matrix.os }}
+  steps:
+    - run: echo hello
+
+    - name: Checkout current branch (fast)
+      uses: actions/checkout@v2"""
+    }
+
+    "compile a job with a long list of scala versions" in {
+      val results = compileJob(
+        WorkflowJob(
+          "bippy",
+          "Bippity Bop Around the Clock",
+          List(
+            WorkflowStep.Run(List("echo hello")),
+            WorkflowStep.Checkout),
+          scalas = List("this", "is", "a", "lot", "of", "versions", "meant", "to", "overflow", "the", "bounds", "checking")),
+        "")
+
+      results mustEqual s"""bippy:
+  name: Bippity Bop Around the Clock
+  strategy:
+    matrix:
+      os: [ubuntu-latest]
+      scala:
+        - this
+        - is
+        - a
+        - lot
+        - of
+        - versions
+        - meant
+        - to
+        - overflow
+        - the
+        - bounds
+        - checking
+      java: [adopt@1.8]
+  runs-on: $${{ matrix.os }}
+  steps:
+    - run: echo hello
+
+    - name: Checkout current branch (fast)
+      uses: actions/checkout@v2"""
+    }
   }
 
   "predicate compilation" >> {