Remove java.desktop dependency from javax.xml.

The only dependency to java.desktop was coming from JAXB.java where a 25
line method from java.beans.Introspector was used to decapitalize a Java
class name.

Partly fixes bazelbuild#7502.
This works around bazelbuild#6799 which seems to take longer than expected because
there is some implementation work left to do.

RELNOTES: None

third_party/jaxb/BUILD

@@ -9,6 +9,6 @@ filegroup(
 
 java_import(
     name = "jaxb",
-    jars = ["jaxb-api-2.3.1.jar"],
+    jars = ["jaxb-api-2.3.1-patched.jar"],
     srcjar = "jaxb-api-2.3.1-sources.jar",
 )

third_party/jaxb/remove-java.desktop.patch

@@ -0,0 +1,54 @@
+diff -ur srcs/javax/xml/bind/JAXB.java srcs-patched/javax/xml/bind/JAXB.java
+--- srcs/javax/xml/bind/JAXB.java	2018-09-12 06:26:24.000000000 +0200
++++ srcs-patched/javax/xml/bind/JAXB.java	2019-04-16 17:17:25.118768524 +0200
+@@ -46,7 +46,6 @@
+ import javax.xml.transform.Source;
+ import javax.xml.transform.stream.StreamResult;
+ import javax.xml.transform.stream.StreamSource;
+-import java.beans.Introspector;
+ import java.io.File;
+ import java.io.IOException;
+ import java.io.InputStream;
+@@ -593,7 +592,30 @@
+     }
+
+     private static String inferName(Class clazz) {
+-        return Introspector.decapitalize(clazz.getSimpleName());
++      String name = clazz.getSimpleName();
++      try {
++        if (!Character.isUpperCase(name.charAt(0))) {
++          return name;
++        } else {
++          try {
++            if(Character.isUpperCase(name.charAt(1))) {
++              return name;
++            } else {
++              char[] c = name.toCharArray();
++              c[0] = Character.toLowerCase(c[0]);
++              return new String(c);
++            }
++          } catch(StringIndexOutOfBoundsException E) {
++            char[] c = new char[1];
++            c[0] = Character.toLowerCase(name.charAt(0));
++            return new String(c);
++          }
++        }
++      } catch(StringIndexOutOfBoundsException E) {
++        return name;
++      } catch(NullPointerException E) {
++        return null;
++      }
+     }
+
+     /**
+diff -ur srcs/module-info.java srcs-patched/module-info.java
+--- srcs/module-info.java	2018-09-12 06:26:24.000000000 +0200
++++ srcs-patched/module-info.java	2019-04-16 17:17:16.038792433 +0200
+@@ -42,7 +42,6 @@
+     requires transitive java.activation;
+     requires transitive java.xml;
+     requires java.logging;
+-    requires java.desktop;
+
+     exports javax.xml.bind;
+     exports javax.xml.bind.annotation;

third_party/jaxb/update.sh

@@ -0,0 +1,11 @@
+#!/bin/bash
+
+set -euxo pipefail
+
+mkdir srcs
+cd srcs
+jar xvf ../jaxb-api-2.3.1-sources.jar
+patch -p1 < ../remove-java.desktop.patch
+rm -rf META-INF
+find . -type f -name \*.java -print0 | xargs -0 javac
+find . -type f -name \*.class -print0 | xargs -0 jar -cvf ../jaxb-api-2.3.1-patched.jar