FULL PRODUCT VERSION :
java version "9-ea"
Java(TM) SE Runtime Environment (build 9-ea+143)
Java HotSpot(TM) 64-Bit Server VM (build 9-ea+143, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
CentOS 7, Linux 3.10.0-327.36.3.el7.x86_64

A DESCRIPTION OF THE PROBLEM :
I'm currently testing OpenJDK 9-ea+143 64-bit on a Linux System (CentOS 7).
JShell is awesome, so I'm testing and playing with it.

Now I found a situation where JShell hangs reproducible:
1. Open JShell
2. Paste the following code including line feed after the second line so both should be executed:
final BigDecimal balance = new BigDecimal("1500000")
final BigDecimal repayment = new BigDecimal("0")

or

final BigDecimal balance = new BigDecimal("1500000");
final BigDecimal repayment = new BigDecimal("0");

The first line ("final") causes a warning. After the warning the shell prompt is displayed, but no further input is possible. JShell hangs, can't be stopped with Ctrl-C, the only option is to kill the process on another shell session.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1. Open JShell
2. Paste the following code including line feed after the second line so both should be executed:
final BigDecimal balance = new BigDecimal("1500000")
final BigDecimal repayment = new BigDecimal("0")

or

final BigDecimal balance = new BigDecimal("1500000");
final BigDecimal repayment = new BigDecimal("0");

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Further input to JShell should be possible
ACTUAL -
JShell hangs

REPRODUCIBILITY :
This bug can be reproduced always.

CUSTOMER SUBMITTED WORKAROUND :
Kill JShell process from another shell session