"We are often asked, especially from our enterprise customers at financial institutions, why we decided to go with PHP and Symfony instead of a Java framework. And as we have actually re-considered alternatives both in 2007 and 2011, we know the answer pretty well. We also know firsthand how much PHP and the PHP ecosystem has matured and progressed the last few years, how Symfony2 and Composer provided a big jump forward, how PHP v7 and Symfony3 is positioned to provide the next, in the end making us very confident in our choice and in recommending it to others. Read-on if you're interested in the topic!"
A good comparison: PHP Flow3 vs Java Spring
PHP and Java Spring - usage comparison
Related but off-topic
How not to hate Spring in 2016
On Flow 3: https://dzone.com/articles/flow3-phps-answer-javas-spring
The following note is kinda old - from 2012
Question one would be: why do they ask for Java? Often big companies only offer Java or .Net environments for productive systems so they might not have the people to productively run PHP applications. I know its not complicated but the maintenance people define what they are running.
Ofter people talk on languages and their features but when the first business use case has to be discussed no framework will save you that amount of time to make it count. Most programming language will somehow solve the issue.
Java is not only RichFaces or JSF. There is a lot to choose from. A LOT. Not an advantage.
Stuff often forgotten is the tool support. Java comes along with a JVM that can be analyzed in detail what it does with its memory, garbage collector, threads and so on. Profilers in Java allow you to identify almost any memory leak within a few hours. Most of the JVM monitoring works in realtime (with about 5% overhead). "
PHP IDEs got way smarter now a days
"You are correct if the first look at Java compared to PHP looks like elephants and horses. (ok the logo of php is an elephant, perfect comparison...). Horses are more flexible to turn around corners but they might not carry that much around. I think from a language perspective Java is still more advanced than PHP. Namespaces, Classes, Type-Safety. These are somewhat available in PHP but still quite new.
Frameworks like Spring allow you to leverage your application on an architectural level and are more than just libraries.
I'm not the biggest Java EE fan, so I'll not complain on that.
A simple approach for you could be Tomcat+Spring+SpringMVC and a template engine for the GUIs. There is also GWT (Vaadin) if you target higher speed client behaviour (still a lot more out there).
There are lightweight approaches in Java too. I agree the standards in Java do have a more fatty tendency.
In my experience Java has no major drawbacks compared to PHP. The language choice will only affect success of the project if people come with less knowledge than required and spend too much time in learning things. And trying to find the right book about Java could be a project by its own :) (counting as an advantage)
But I have no doubts PHP would allow you to finish the project.
I would rather look into the goals and requirements before choosing the technology. This often implies or simplifies a decision.
Related: Spring Framework vs the rest of the world
Related: PHP and Java Comparison for Web Projects
Micro Services Frameworks in Different Languages: https://github.com/mfornos/awesome-microservices#java-vm