Use WinReg to set JAVA_HOME (#38)

* Use WinReg to set JAVA_HOME

* Add back using Base.Dates

REQUIRE

@@ -1,2 +1,3 @@
 julia 0.4
 Compat 0.8.4
+WinReg

src/JavaCall.jl

@@ -5,8 +5,8 @@ export JavaObject, JavaMetaClass,
        @jimport, jcall, jfield, isnull,
        getname, listmethods, getreturntype, getparametertypes
 
-# using Debug
 using Base.Dates
+using WinReg
 using Compat
 import Compat.String
 

src/jvm.jl

@@ -16,6 +16,12 @@ const JNI_ENOMEM       = convert(Cint, -4)              #/* not enough memory */
 const JNI_EEXIST       = convert(Cint, -5)              #/* VM already created */
 const JNI_EINVAL       = convert(Cint, -6)              #/* invalid arguments */
 
+function javahome_winreg()
+    keypath = "SOFTWARE\\JavaSoft\\Java Development Kit"
+	value = querykey(WinReg.HKEY_LOCAL_MACHINE, keypath, "CurrentVersion")
+	keypath *= "\\"*value
+	return querykey(WinReg.HKEY_LOCAL_MACHINE, keypath, "JavaHome")
+end
 
 @static is_unix() ? (global const libname = "libjvm") : (global const libname = "jvm")
 
@@ -25,7 +31,11 @@ function findjvm()
 
     if haskey(ENV,"JAVA_HOME")
         push!(javahomes,ENV["JAVA_HOME"])
+    else
+        @static is_windows() ? ENV["JAVA_HOME"] = javahome_winreg() : nothing
+        @static is_windows() ? push!(javahomes, ENV["JAVA_HOME"]) : nothing
     end
+
     if isfile("/usr/libexec/java_home")
         push!(javahomes,chomp(readstring(`/usr/libexec/java_home`)))
     end