diff --git a/core/pom.xml b/core/pom.xml
index bbcf5e5781..5dc03bcf05 100644
--- a/core/pom.xml
+++ b/core/pom.xml
@@ -87,11 +87,6 @@
       <version>1.8.3</version>
       <optional>true</optional>
     </dependency>
-    <dependency>
-      <groupId>com.google.guava</groupId>
-      <artifactId>guava</artifactId>
-      <version>11.0.1</version>
-    </dependency>
     <dependency>
       <groupId>org.kohsuke</groupId>
       <artifactId>asm5</artifactId>
diff --git a/core/src/main/java/org/kohsuke/stapler/AbstractTearOff.java b/core/src/main/java/org/kohsuke/stapler/AbstractTearOff.java
index 07907e6b26..c109d198eb 100644
--- a/core/src/main/java/org/kohsuke/stapler/AbstractTearOff.java
+++ b/core/src/main/java/org/kohsuke/stapler/AbstractTearOff.java
@@ -23,14 +23,16 @@
 
 package org.kohsuke.stapler;
 
-import com.google.common.cache.Cache;
-import com.google.common.cache.CacheBuilder;
 import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
 
 import java.io.File;
+import java.lang.ref.Reference;
+import java.lang.ref.SoftReference;
 import java.net.URI;
 import java.net.URISyntaxException;
 import java.net.URL;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 import java.util.regex.Matcher;
@@ -52,13 +54,13 @@ public abstract class AbstractTearOff<CLT,S,E extends Exception> extends Caching
 
     private static final class ExpirableCacheHit<S> {
         private final long timestamp;
-        private final S script;
+        private final Reference<S> script;
         ExpirableCacheHit(long timestamp, S script) {
             this.timestamp = timestamp;
-            this.script = script;
+            this.script = new SoftReference<>(script);
         }
     }
-    private final Cache<URL, ExpirableCacheHit<S>> cachedScripts = CacheBuilder.newBuilder().softValues().build();
+    private final Map<String, ExpirableCacheHit<S>> cachedScripts = new ConcurrentHashMap<>();
 
     protected AbstractTearOff(MetaClass owner, Class<CLT> cltClass) {
         this.owner = owner;
@@ -122,7 +124,7 @@ public S resolveScript(String name) throws E {
                         LOGGER.log(Level.FINE, "no timestamp associated with {0}", file);
                         return parseScript(res);
                     } else {
-                        ExpirableCacheHit<S> cached = cachedScripts.getIfPresent(res);
+                        ExpirableCacheHit<S> cached = cachedScripts.get(res.toString());
                         if (cached == null) {
                             S script;
                             if (LOGGER.isLoggable(Level.FINE)) {
@@ -136,15 +138,25 @@ public S resolveScript(String name) throws E {
                                 LOGGER.log(Level.FINE, "cache miss on {0}", res);
                                 script = parseScript(res);
                             }
-                            cachedScripts.put(res, new ExpirableCacheHit<>(timestamp, script));
+                            cachedScripts.put(res.toString(), new ExpirableCacheHit<>(timestamp, script));
                             return script;
-                        } else if (timestamp == cached.timestamp) {
-                            LOGGER.log(Level.FINE, "cache hit on {0}", res);
-                            return cached.script;
                         } else {
-                            LOGGER.log(Level.FINE, "expired cache hit on {0}", res);
-                            S script = parseScript(res);
-                            cachedScripts.put(res, new ExpirableCacheHit<>(timestamp, script));
+                            S script;
+                            if (timestamp == cached.timestamp) {
+                                script = cached.script.get();
+                                if (script == null) {
+                                    LOGGER.log(Level.FINE, "cache hit on {0} but value collected", res);
+                                } else {
+                                    LOGGER.log(Level.FINE, "cache hit on {0}", res);
+                                }
+                            } else {
+                                LOGGER.log(Level.FINE, "expired cache hit on {0}", res);
+                                script = null;
+                            }
+                            if (script == null) {
+                                script = parseScript(res);
+                                cachedScripts.put(res.toString(), new ExpirableCacheHit<>(timestamp, script));
+                            }
                             return script;
                         }
                     }
diff --git a/core/src/main/java/org/kohsuke/stapler/CachingScriptLoader.java b/core/src/main/java/org/kohsuke/stapler/CachingScriptLoader.java
index 0bb83135c7..8e779e33f2 100644
--- a/core/src/main/java/org/kohsuke/stapler/CachingScriptLoader.java
+++ b/core/src/main/java/org/kohsuke/stapler/CachingScriptLoader.java
@@ -1,10 +1,11 @@
 package org.kohsuke.stapler;
 
-import com.google.common.cache.CacheBuilder;
-import com.google.common.cache.CacheLoader;
-import com.google.common.cache.LoadingCache;
-
+import java.lang.ref.Reference;
+import java.lang.ref.SoftReference;
 import java.net.URL;
+import java.util.Map;
+import java.util.Optional;
+import java.util.concurrent.ConcurrentHashMap;
 
 /**
  * Convenient base class for caching loaded scripts.
@@ -22,20 +23,8 @@ public abstract class CachingScriptLoader<S, E extends Exception> {
      *
      * So it's important to allow Scripts to be garbage collected.
      * This is not an ideal fix, but it works.
-     *
-     * {@link Optional} is used as Google Collection doesn't allow null values in a map.
      */
-    private final LoadingCache<String,Optional<S>> scripts = CacheBuilder.newBuilder().softValues().build(new CacheLoader<String, Optional<S>>() {
-        public Optional<S> load(String from) {
-            try {
-                return Optional.create(loadScript(from));
-            } catch (RuntimeException e) {
-                throw e;    // pass through
-            } catch (Exception e) {
-                throw new ScriptLoadException(e);
-            }
-        }
-    });
+    private final Map<String, Optional<Reference<S>>> scripts = new ConcurrentHashMap<>();
 
     /**
      * Locates the view script of the given name.
@@ -56,10 +45,24 @@ public Optional<S> load(String from) {
      * @return null if none was found.
      */
     public S findScript(String name) throws E {
-        if (MetaClass.NO_CACHE) 
+        if (MetaClass.NO_CACHE) {
             return loadScript(name);
-        else
-            return scripts.getUnchecked(name).get();
+        } else {
+            Optional<Reference<S>> sr = scripts.get(name);
+            S s;
+            if (sr == null) { // never before computed
+                s = null;
+            } else if (!sr.isPresent()) { // cached as null
+                return null;
+            } else { // cached as non-null; may or may not still have value
+                s = sr.get().get();
+            }
+            if (s == null) { // needs to be computed
+                s = loadScript(name);
+                scripts.put(name, s == null ? Optional.empty() : Optional.of(new SoftReference<>(s)));
+            }
+            return s;
+        }
     }
 
     /**
@@ -70,8 +73,8 @@ public S findScript(String name) throws E {
     /**
      * Discards the cached script.
      */
-    public synchronized void clearScripts() {
-        scripts.invalidateAll();
+    public void clearScripts() {
+        scripts.clear();
     }
 
     protected abstract URL getResource(String name);
diff --git a/core/src/main/java/org/kohsuke/stapler/Function.java b/core/src/main/java/org/kohsuke/stapler/Function.java
index 63678f80bf..8d97042d0d 100644
--- a/core/src/main/java/org/kohsuke/stapler/Function.java
+++ b/core/src/main/java/org/kohsuke/stapler/Function.java
@@ -23,9 +23,6 @@
 
 package org.kohsuke.stapler;
 
-import com.google.common.cache.CacheBuilder;
-import com.google.common.cache.CacheLoader;
-import com.google.common.cache.LoadingCache;
 import org.apache.commons.lang.StringUtils;
 import org.kohsuke.stapler.interceptor.Interceptor;
 import org.kohsuke.stapler.interceptor.InterceptorAnnotation;
@@ -38,7 +35,6 @@
 import java.lang.invoke.MethodHandle;
 import java.lang.invoke.WrongMethodTypeException;
 import java.lang.reflect.AnnotatedElement;
-import java.lang.reflect.Executable;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
@@ -195,7 +191,7 @@ Object bindAndInvoke(Object o, StaplerRequest req, StaplerResponse rsp, Object..
                 }
 
                 // if the databinding method is provided, call that
-                Function binder = PARSE_METHODS.getUnchecked(t);
+                Function binder = PARSE_METHODS.get(t);
                 if (binder!=RETURN_NULL) {
                     arguments[i] = binder.bindAndInvoke(null,req,rsp);
                     continue;
@@ -216,7 +212,7 @@ Object bindAndInvoke(Object o, StaplerRequest req, StaplerResponse rsp, Object..
      * Computing map that discovers the static 'fromStapler' method from a class.
      * The discovered method will be returned as a Function so that the invocation can do parameter injections.
      */
-    private static final LoadingCache<Class,Function> PARSE_METHODS;
+    private static final ClassValue<Function> PARSE_METHODS;
     private static final Function RETURN_NULL;
 
     static {
@@ -226,8 +222,9 @@ Object bindAndInvoke(Object o, StaplerRequest req, StaplerResponse rsp, Object..
             throw new AssertionError(e);    // impossible
         }
 
-        PARSE_METHODS = CacheBuilder.newBuilder().weakKeys().build(new CacheLoader<Class,Function>() {
-            public Function load(Class from) {
+        PARSE_METHODS = new ClassValue<Function>() {
+            @Override
+            public Function computeValue(Class<?> from) {
                 // MethdFunction for invoking a static method as a static method
                 FunctionList methods = new ClassDescriptor(from).methods.name("fromStapler");
                 switch (methods.size()) {
@@ -259,7 +256,7 @@ public Object invoke(StaplerRequest req, StaplerResponse rsp, Object o, Object..
                     };
                 }
             }
-        });
+        };
     }
 
     /**
diff --git a/core/src/main/java/org/kohsuke/stapler/Optional.java b/core/src/main/java/org/kohsuke/stapler/Optional.java
deleted file mode 100644
index 3ae2ff7a60..0000000000
--- a/core/src/main/java/org/kohsuke/stapler/Optional.java
+++ /dev/null
@@ -1,51 +0,0 @@
-/*
- * Copyright (c) 2004-2010, Kohsuke Kawaguchi
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without modification, are permitted provided
- * that the following conditions are met:
- *
- *     * Redistributions of source code must retain the above copyright notice, this list of
- *       conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above copyright notice, this list of
- *       conditions and the following disclaimer in the documentation and/or other materials
- *       provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS
- * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
- * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
- * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
- * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
- * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
- * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
- * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-
-package org.kohsuke.stapler;
-
-/**
- * Represents a T value or no value at all. Used to work around the lack of null value in the computing map.
- *
- * @author Kohsuke Kawaguchi
- */
-final class Optional<T> {
-    private final T value;
-
-    Optional(T value) {
-        this.value = value;
-    }
-
-    public T get() { return value; }
-
-
-    private static Optional NONE = new Optional(null);
-
-    public static <T> Optional<T> none() {
-        return NONE;
-    }
-
-    public static <T> Optional<T> create(T value) {
-        if (value==null)    return NONE;    // cache
-        return new Optional<T>(value);
-    }
-}
diff --git a/core/src/main/java/org/kohsuke/stapler/ScriptLoadException.java b/core/src/main/java/org/kohsuke/stapler/ScriptLoadException.java
index accce3a53b..78d872dded 100644
--- a/core/src/main/java/org/kohsuke/stapler/ScriptLoadException.java
+++ b/core/src/main/java/org/kohsuke/stapler/ScriptLoadException.java
@@ -24,10 +24,9 @@
 package org.kohsuke.stapler;
 
 /**
- * Indicates a failure to load a script.
- *
- * @author Kohsuke Kawaguchi
+ * @deprecated No longer used.
  */
+@Deprecated
 public class ScriptLoadException extends RuntimeException {
     public ScriptLoadException(String message, Throwable cause) {
         super(message, cause);