I was very happy with Java-the-language as well, back when I worked with it. Calling this "a huge problem" is of course an exaggeration - but it is very much a regular annoyance and it is one almost inherent to checked exceptions.
I also don't agree that IOException should not have been checked. If there is any purpose for checked exceptions at all, than IOException is the most important one to check. It is the quintessential example of a good use of exceptions. It is also the one for which it most likely that the code can automatically recover - you can retry the operation, use a fallback file/address/DNS server, you can use a default value if some config file is missing, etc. I don't think there is any other clear catgeory of errors that is more likely to be usefully handled than IOException.
I also don't agree that IOException should not have been checked. If there is any purpose for checked exceptions at all, than IOException is the most important one to check. It is the quintessential example of a good use of exceptions. It is also the one for which it most likely that the code can automatically recover - you can retry the operation, use a fallback file/address/DNS server, you can use a default value if some config file is missing, etc. I don't think there is any other clear catgeory of errors that is more likely to be usefully handled than IOException.