diff --git a/ext/java/org/jruby/ext/psych/PsychParser.java b/ext/java/org/jruby/ext/psych/PsychParser.java
index 472327b8..05374e38 100644
--- a/ext/java/org/jruby/ext/psych/PsychParser.java
+++ b/ext/java/org/jruby/ext/psych/PsychParser.java
@@ -236,6 +236,16 @@ private static StreamReader readerForString(ThreadContext context, RubyString st
     public IRubyObject parse(ThreadContext context, IRubyObject handler, IRubyObject yaml, IRubyObject path) {
         Ruby runtime = context.runtime;
 
+        // The parser calls back into Ruby for every event, so a handler can call
+        // Psych::Parser#parse again on the same object, which would replace the
+        // parser the loop below is still driving.
+        if (parsing) {
+            throw runtime.newRaiseException(
+                    (RubyClass) runtime.getModule("Psych").getConstant("Exception"),
+                    "parser is already parsing, it cannot be reused from a handler callback");
+        }
+        parsing = true;
+
         try {
             LoadSettings loadSettings = loadSettingsBuilder.build();
             parser = new ParserImpl(loadSettings, new ScannerImpl(loadSettings, readerFor(context, yaml, loadSettings)));
@@ -324,6 +334,8 @@ public IRubyObject parse(ThreadContext context, IRubyObject handler, IRubyObject
         } catch (Throwable t) {
             Helpers.throwException(t);
             return this;
+        } finally {
+            parsing = false;
         }
 
         return this;
@@ -567,6 +579,7 @@ private LoadSettings buildSettings() {
 
     private Parser parser;
     private Event event;
+    private boolean parsing;
     private final LoadSettingsBuilder loadSettingsBuilder;
     private final CallSites sites;
 
diff --git a/test/psych/test_parser.rb b/test/psych/test_parser.rb
index aeb74244..4b0bd9bf 100644
--- a/test/psych/test_parser.rb
+++ b/test/psych/test_parser.rb
@@ -118,8 +118,6 @@ def event_location start_line, start_column, end_line, end_column
     end
 
     def test_parse_is_not_reentrant
-      pend "Failing on JRuby" if RUBY_PLATFORM =~ /java/
-
       handler = ReentrantHandler.new
       handler.inner_yaml = "--- inner\n"
       parser = Psych::Parser.new handler
@@ -139,8 +137,6 @@ def test_parse_is_not_reentrant
     end
 
     def test_parse_is_not_reentrant_with_invalid_inner_document
-      pend "Failing on JRuby" if RUBY_PLATFORM =~ /java/
-
       handler = ReentrantHandler.new
       handler.inner_yaml = "--- \x00bad\n"
       parser = Psych::Parser.new handler