This exception occurs when you attempt Class.forName("org"):

java.lang.StringIndexOutOfBoundsException: String index out of range: 3
	at java.lang.String.charAt(String.java:658) ~[?:1.8.0_72]
	at org.apache.catalina.loader.WebappClassLoaderBase.filter(WebappClassLoaderBase.java:2780) ~[catalina.jar:8.0.32]
	at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1253) ~[catalina.jar:8.0.32]
	at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1142) ~[catalina.jar:8.0.32]
	at java.lang.Class.forName0(Native Method) ~[?:1.8.0_72]
	at java.lang.Class.forName(Class.java:348) ~[?:1.8.0_72]


This is a bug - Class.forName() should never throw StringIndexOutOfBoundsException. Instead, it should either return the class named "org" or throw a ClassNotFoundException.

Fix:

--- WebappClassLoaderBase.java.orig	2016-04-06 13:23:39.000000000 -0500
+++ WebappClassLoaderBase.java	2016-04-06 13:25:24.000000000 -0500
@@ -2751,7 +2751,7 @@
             return false;
 
         char ch;
-        if (name.startsWith("javax")) {
+        if (name.startsWith("javax") && name.length() > 5) {
             /* 5 == length("javax") */
             ch = name.charAt(5);
             if (isClassName && ch == '.') {
@@ -2775,7 +2775,7 @@
                     return true;
                 }
             }
-        } else if (name.startsWith("org")) {
+        } else if (name.startsWith("org") && name.length() > 3) {
             /* 3 == length("org") */
             ch = name.charAt(3);
             if (isClassName && ch == '.') {