Earlier this year Google announced that Chrome Version 42 would disable the NPAPI but leave an option to re-enable it. However, Google has now announced that from September 2015 they will be completely disabling NPAPI within Chrome.
The NPAPI is the architecture that the Oracle Java Plugin relies upon. This plugin is required by Java Applets. This means that from September 2015 the Java uploader will no longer work within Chrome.
If you want to continue using the Java uploader you will need to use another browser such as Firefox or Internet Explorer. More information on this can be found here.
Thankfully, if you want to carry on using Chrome there are other ways of uploading files; My Images > Collection and File Defaults > File Uploads (the html 5 uploader is the most popular and the most updated).