Looking at my own server logs, I have several such entries spread over several weeks from several different IP addresses. All with similar - but slightly different - User Agents.
Most, but not all of the IP Addresses appear to be based in Romania.
Here's a sampling of my logs:
[02/Aug/2011:23:20:32 +0000] "GET /assets/js/,data:c,complete:function(a,b,c)%7bc=a.responseText,a.isResolved()&&(a.done(function(a)%7bc=a%7d),i.html(g?f( HTTP/1.1" 200 203 "-" "Java/1.6.0_04"
[03/Aug/2011:05:06:30 +0000] "GET /assets/js/,data:c,complete:function(a,b,c){c=a.responseText,a.isResolved()&&(a.done(function(a){c=a}),i.html(g?f( HTTP/1.1" 200 203 "-" "Java/1.6.0_04"
[04/Aug/2011:12:03:35 +0000] "GET /assets/js/,data:c,complete:function(a,b,c)%7bc=a.responseText,a.isResolved()&&(a.done(function(a)%7bc=a%7d),i.html(g?f( HTTP/1.1" 200 203 "-" "Java/1.6.0_11"
[06/Aug/2011:15:34:00 +0000] "GET /assets/js/,data:c,complete:function(a,b,c)%7bc=a.responseText,a.isResolved()&&(a.done(function(a)%7bc=a%7d),i.html(g?f( HTTP/1.1" 200 203 "-" "Java/1.6.0_22"
[06/Aug/2011:18:20:46 +0000] "GET /assets/js/,data:c,complete:function(a,b,c){c=a.responseText,a.isResolved()&&(a.done(function(a){c=a}),i.html(g?f( HTTP/1.1" 200 203 "-" "Java/1.6.0_22"
[06/Aug/2011:19:40:11 +0000] "GET /assets/js/,data:c,complete:function(a,b,c)%7bc=a.responseText,a.isResolved()&&(a.done(function(a)%7bc=a%7d),i.html(g?f( HTTP/1.1" 200 203 "-" "Java/1.6.0_25"
[07/Aug/2011:07:55:24 +0000] "GET /assets/js/,data:c,complete:function(a,b,c)%7bc=a.responseText,a.isResolved()&&(a.done(function(a)%7bc=a%7d),i.html(g?f( HTTP/1.1" 200 203 "-" "Java/1.6.0_20"
[10/Aug/2011:09:07:47 +0000] "GET /assets/js/,data:c,complete:function(a,b,c){c=a.responseText,a.isResolved()&&(a.done(function(a){c=a}),i.html(g?f( HTTP/1.1" 200 203 "-" "Java/1.6.0_22"
[14/Aug/2011:14:53:58 +0000] "GET /assets/js/,data:c,complete:function(a,b,c)%7bc=a.responseText,a.isResolved()&&(a.done(function(a)%7bc=a%7d),i.html(g?f( HTTP/1.1" 200 203 "-" "Java/1.6.0_04"
[16/Aug/2011:21:04:50 +0000] "GET /assets/js/,data:c,complete:function(a,b,c)%7bc=a.responseText,a.isResolved()&&(a.done(function(a)%7bc=a%7d),i.html(g?f( HTTP/1.1" 200 203 "-" "Java/1.6.0_04"
[17/Aug/2011:09:19:12 +0000] "GET /assets/js/,data:c,complete:function(a,b,c){c=a.responseText,a.isResolved()&&(a.done(function(a){c=a}),i.html(g?f( HTTP/1.1" 200 203 "-" "Java/1.6.0_04"
[22/Aug/2011:01:50:44 +0000] "GET /assets/js/,data:c,complete:function(a,b,c)%7bc=a.responseText,a.isResolved()&&(a.done(function(a)%7bc=a%7d),i.html(g?f( HTTP/1.1" 200 203 "-" "Java/1.6.0_26"
[22/Aug/2011:19:13:00 +0000] "GET /assets/js/,data:c,complete:function(a,b,c)%7bc=a.responseText,a.isResolved()&&(a.done(function(a)%7bc=a%7d),i.html(g?f( HTTP/1.1" 200 203 "-" "Java/1.6.0_04"
[26/Aug/2011:18:15:06 +0000] "GET /assets/js/,data:c,complete:function(a,b,c)%7bc=a.responseText,a.isResolved()&&(a.done(function(a)%7bc=a%7d),i.html(g?f( HTTP/1.1" 200 203 "-" "Java/1.6.0_04"
[08/Sep/2011:00:00:01 +0000] "GET /assets/js/,data:c,complete:function(a,b,c){c=a.responseText,a.isResolved()&&(a.done(function(a){c=a}),i.html(g?f( HTTP/1.1" 200 203 "-" "Java/1.6.0_04"
[10/Sep/2011:16:09:39 +0000] "GET /assets/js/,data:c,complete:function(a,b,c){c=a.responseText,a.isResolved()&&(a.done(function(a){c=a}),i.html(g?f( HTTP/1.1" 200 203 "-" "Java/1.6.0_04"
[12/Sep/2011:14:50:15 +0000] "GET /assets/js/,data:c,complete:function(a,b,c)%7bc=a.responseText,a.isResolved()&&(a.done(function(a)%7bc=a%7d),i.html(g?f( HTTP/1.1" 200 203 "-" "Java/1.6.0_04"
[13/Sep/2011:14:25:08 +0000] "GET /assets/js/,data:c,complete:function(a,b,c){c=a.responseText,a.isResolved()&&(a.done(function(a){c=a}),i.html(g?f( HTTP/1.1" 200 203 "-" "Java/1.6.0_04"
[13/Sep/2011:16:14:05 +0000] "GET /assets/js/,data:c,complete:function(a,b,c){c=a.responseText,a.isResolved()&&(a.done(function(a){c=a}),i.html(g?f( HTTP/1.1" 200 203 "-" "Java/1.6.0_04"
While I don't believe this misguided bot is causing any harm, I'm going to be following the advice of this blog and block all hits from Java User Agents. As a preventative measure, you may want to do the same.