FULL PRODUCT VERSION :
java version "9-ae"
Java(TM) SE Runtime Environment (build 9-ea+124)
Java HotSpot(TM) Client VM (build 9-ea+124, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Windows 7 version 6.1.7601

A DESCRIPTION OF THE PROBLEM :
After installing build 124 and the JRE on my Windows machine (and properly setting the PATH environmental variable), I can no longer use java.exe unless I execute it either

(1) directly from its bin directory, or

(2) use an explicit, full path qualification.

From any directory other than its bin dir, if I try to run java.exe without explicitly specifying its path, I see the following message when java.exe attempts to execute:

Error: could not file java.dll
Error: could not find Java SE Runtime environment.

Since the PATH command is properly set (because I can run javac from any dir), I don't understand why java.exe will not run from any dir on my system unless the path is (redundantly) specified.

When using build 120, which did not install the JRE, I was able to run java.exe without trouble. Thus, I think that something in the installation process of the JRE is causing java.exe to not work.

To be clear, lets work through an example. Assume that I am currently in a directory called MyDir. java.exe will NOT run if I enter the following:

c:\MyDir>java

In this case, I see the error messages shown above.

However, java.exe WILL work if I use a full path qualification:

c:\MyDir>c:\\"program files (x86)"\java\jdk-9\bin\java

java.exe will also work if I execute it from its bin dir.

In all cases, javac.exe executes correctly. For example,

c:\MyDir>javac MyClass.java

works fine, without any trouble. Only java.exe has the problem.

Again, because my PATH environmental variable is set to the JDK bin
directory (proven by the fact that I can execute javac from any dir), I
don't understand why java.exe will not work without an explicit (and
redundant) full path qualification.

One last point: I have run all versions of Java since 1.0 and never had a problem like this. This includes JDK 8, u77. Thus, the behavior that I am seeing differs from all previous versions of Java. I am a very experienced Java programmer.


REGRESSION. Last worked in version 8u77

ADDITIONAL REGRESSION INFORMATION:
java version "9-ae"
Java(TM) SE Runtime Environment (build 9-ea+124)
Java HotSpot(TM) Client VM (build 9-ea+124, mixed mode)

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
See Description


REPRODUCIBILITY :
This bug can be reproduced always.