Migration of Java Application from 1.5 to 1.8

Question

We are working in the project of migrating a application(built in java 5) to java 8 for better performance,

But , we are not sure that 1. upgrade an environment or 2.Build that complete app in java 8 from scratch,

and how it will improve the performance !

And we know that, There will be some Deprecated API's from version to version. so, while upgrading is it possible to get error or miss some functionality ?

How can We rectify that?

Please comment your suggestions !

Answer 1

Java has full backward compatability, So

1. If you just change java version then it will not have any errors as java8 is fully compatible with previous java versions.
2. If you want to improve performance using java8, Then you have to read java8 release notes to know where you can get faster alternative of current code and then you can only re-wright that functionality only