diff --git a/src/java.base/share/classes/sun/security/action/GetPropertyAction.java b/src/java.base/share/classes/sun/security/action/GetPropertyAction.java
index 8768cc3e0f2..347072de9f9 100644
--- a/src/java.base/share/classes/sun/security/action/GetPropertyAction.java
+++ b/src/java.base/share/classes/sun/security/action/GetPropertyAction.java
@@ -224,4 +224,37 @@ public class GetPropertyAction implements PrivilegedAction<String> {
             return def;
         }
     }
+
+    /**
+     * Convenience method for fetching System property values that are booleans.
+     *
+     * @param prop the name of the System property
+     * @param def a default value
+     * @param dbg a Debug object, if null no debug messages will be sent
+     *
+     * @return a boolean value corresponding to the value in the System property.
+     *      If the property value is neither "true" or "false", the default value
+     *      will be returned.
+     */
+    public static boolean privilegedGetBooleanProp(String prop, boolean def, Debug dbg) {
+        String rawPropVal = privilegedGetProperty(prop, "");
+        if ("".equals(rawPropVal)) {
+            return def;
+        }
+
+        String lower = rawPropVal.toLowerCase(Locale.ROOT);
+        if ("true".equals(lower)) {
+            return true;
+        } else if ("false".equals(lower)) {
+            return false;
+        } else {
+            if (dbg != null) {
+                dbg.println("Warning: Unexpected value for " + prop +
+                            ": " + rawPropVal +
+                            ". Using default value: " + def);
+            }
+            return def;
+        }
+    }
+
 }
diff --git a/src/java.base/share/classes/sun/security/provider/certpath/OCSP.java b/src/java.base/share/classes/sun/security/provider/certpath/OCSP.java
index febff793b69..6f1f7b6ad73 100644
--- a/src/java.base/share/classes/sun/security/provider/certpath/OCSP.java
+++ b/src/java.base/share/classes/sun/security/provider/certpath/OCSP.java
@@ -105,7 +105,7 @@ public final class OCSP {
      * problems.
      */
     private static final boolean USE_GET = initializeBoolean(
-            "com.sun.security.ocsp.useget", "true");
+            "com.sun.security.ocsp.useget", true);
 
     /**
      * Initialize the timeout length by getting the OCSP timeout
@@ -121,9 +121,9 @@ public final class OCSP {
         return timeoutVal;
     }
 
-    private static boolean initializeBoolean(String prop, String def) {
-        String flag = GetPropertyAction.privilegedGetProperty(prop, def);
-        boolean value = Boolean.parseBoolean(flag);
+    private static boolean initializeBoolean(String prop, boolean def) {
+        boolean value =
+                GetPropertyAction.privilegedGetBooleanProp(prop, def, debug);
         if (debug != null) {
             debug.println(prop + " set to " + value);
         }
diff --git a/test/jdk/java/security/cert/CertPathValidator/OCSP/GetAndPostTests.java b/test/jdk/java/security/cert/CertPathValidator/OCSP/GetAndPostTests.java
index 85a2fd77fa6..478e94572bc 100644
--- a/test/jdk/java/security/cert/CertPathValidator/OCSP/GetAndPostTests.java
+++ b/test/jdk/java/security/cert/CertPathValidator/OCSP/GetAndPostTests.java
@@ -32,6 +32,7 @@
  *          java.base/sun.security.x509
  * @run main/othervm GetAndPostTests
  * @run main/othervm -Dcom.sun.security.ocsp.useget=false GetAndPostTests
+ * @run main/othervm -Dcom.sun.security.ocsp.useget=foo GetAndPostTests
  */
 
 import java.io.ByteArrayInputStream;
diff --git a/test/jdk/java/security/testlibrary/SimpleOCSPServer.java b/test/jdk/java/security/testlibrary/SimpleOCSPServer.java
index f4222414dc6..e1883edeec5 100644
--- a/test/jdk/java/security/testlibrary/SimpleOCSPServer.java
+++ b/test/jdk/java/security/testlibrary/SimpleOCSPServer.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2015, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -702,6 +702,9 @@ public class SimpleOCSPServer {
      * responses.
      */
     private class OcspHandler implements Runnable {
+        private final boolean USE_GET =
+            !System.getProperty("com.sun.security.ocsp.useget", "").equals("false");
+
         private final Socket sock;
         InetSocketAddress peerSockAddr;
 
@@ -874,6 +877,12 @@ public class SimpleOCSPServer {
             // Okay, make sure we got what we needed from the header, then
             // read the remaining OCSP Request bytes
             if (properContentType && length >= 0) {
+                if (USE_GET && length <= 255) {
+                    // Received a small POST request. Check that our client code properly
+                    // handled the relevant flag. We expect small GET requests, unless
+                    // explicitly disabled.
+                    throw new IOException("Should have received small GET, not POST.");
+                }
                 byte[] ocspBytes = new byte[length];
                 inStream.read(ocspBytes);
                 return new LocalOcspRequest(ocspBytes);