As seen in test run, dozens of threads --

"Thread-102" #4176 daemon prio=5 os_prio=0 tid=0x00007f68e83d1000 nid=0x678f in Object.wait() [0x00007f6921de4000]
   java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait(java.base@9-internal/Native Method)
- waiting on <no object reference available>
at java.lang.Object.wait(java.base@9-internal/Object.java:516)
at jdk.internal.jshell.tool.StopDetectingInputStream.waitInputNeeded(jdk.jshell@9-internal/StopDetectingInputStream.java:140)
- waiting to re-lock in wait() <0x00000005ec3da470> (a jdk.internal.jshell.tool.StopDetectingInputStream)
at jdk.internal.jshell.tool.StopDetectingInputStream.access$000(jdk.jshell@9-internal/StopDetectingInputStream.java:32)
at jdk.internal.jshell.tool.StopDetectingInputStream$1.run(jdk.jshell@9-internal/StopDetectingInputStream.java:64)

"Thread-100" #4166 daemon prio=5 os_prio=0 tid=0x00007f68e83d1800 nid=0x6732 in Object.wait() [0x00007f69219e0000]
   java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait(java.base@9-internal/Native Method)
- waiting on <no object reference available>
at java.lang.Object.wait(java.base@9-internal/Object.java:516)
at jdk.internal.jshell.tool.StopDetectingInputStream.waitInputNeeded(jdk.jshell@9-internal/StopDetectingInputStream.java:140)
- waiting to re-lock in wait() <0x00000005f7fbfee8> (a jdk.internal.jshell.tool.StopDetectingInputStream)
at jdk.internal.jshell.tool.StopDetectingInputStream.access$000(jdk.jshell@9-internal/StopDetectingInputStream.java:32)
at jdk.internal.jshell.tool.StopDetectingInputStream$1.run(jdk.jshell@9-internal/StopDetectingInputStream.java:64)

"Thread-98" #4156 daemon prio=5 os_prio=0 tid=0x00007f68e8404800 nid=0x66d5 in Object.wait() [0x00007f69218df000]
   java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait(java.base@9-internal/Native Method)
- waiting on <no object reference available>
at java.lang.Object.wait(java.base@9-internal/Object.java:516)
at jdk.internal.jshell.tool.StopDetectingInputStream.waitInputNeeded(jdk.jshell@9-internal/StopDetectingInputStream.java:140)
- waiting to re-lock in wait() <0x00000005e299af10> (a jdk.internal.jshell.tool.StopDetectingInputStream)
at jdk.internal.jshell.tool.StopDetectingInputStream.access$000(jdk.jshell@9-internal/StopDetectingInputStream.java:32)
at jdk.internal.jshell.tool.StopDetectingInputStream$1.run(jdk.jshell@9-internal/StopDetectingInputStream.java:64)

"Thread-96" #4146 daemon prio=5 os_prio=0 tid=0x00007f68e82fe000 nid=0x6678 in Object.wait() [0x00007f6921be2000]
   java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait(java.base@9-internal/Native Method)
- waiting on <no object reference available>
at java.lang.Object.wait(java.base@9-internal/Object.java:516)
at jdk.internal.jshell.tool.StopDetectingInputStream.waitInputNeeded(jdk.jshell@9-internal/StopDetectingInputStream.java:140)
- waiting to re-lock in wait() <0x00000005e299ae28> (a jdk.internal.jshell.tool.StopDetectingInputStream)
at jdk.internal.jshell.tool.StopDetectingInputStream.access$000(jdk.jshell@9-internal/StopDetectingInputStream.java:32)
at jdk.internal.jshell.tool.StopDetectingInputStream$1.run(jdk.jshell@9-internal/StopDetectingInputStream.java:64)

"Thread-94" #4136 daemon prio=5 os_prio=0 tid=0x00007f68e82d7000 nid=0x661b in Object.wait() [0x00007f6921ee5000]
   java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait(java.base@9-internal/Native Method)
- waiting on <no object reference available>
at java.lang.Object.wait(java.base@9-internal/Object.java:516)
at jdk.internal.jshell.tool.StopDetectingInputStream.waitInputNeeded(jdk.jshell@9-internal/StopDetectingInputStream.java:140)
- waiting to re-lock in wait() <0x00000005e30eada0> (a jdk.internal.jshell.tool.StopDetectingInputStream)
at jdk.internal.jshell.tool.StopDetectingInputStream.access$000(jdk.jshell@9-internal/StopDetectingInputStream.java:32)
at jdk.internal.jshell.tool.StopDetectingInputStream$1.run(jdk.jshell@9-internal/StopDetectingInputStream.java:64)

"Thread-92" #4126 daemon prio=5 os_prio=0 tid=0x00007f68e81de000 nid=0x65bc in Object.wait() [0x00007f6921fe6000]
   java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait(java.base@9-internal/Native Method)
- waiting on <no object reference available>
at java.lang.Object.wait(java.base@9-internal/Object.java:516)
at jdk.internal.jshell.tool.StopDetectingInputStream.waitInputNeeded(jdk.jshell@9-internal/StopDetectingInputStream.java:140)
- waiting to re-lock in wait() <0x00000005e299af38> (a jdk.internal.jshell.tool.StopDetectingInputStream)
at jdk.internal.jshell.tool.StopDetectingInputStream.access$000(jdk.jshell@9-internal/StopDetectingInputStream.java:32)
at jdk.internal.jshell.tool.StopDetectingInputStream$1.run(jdk.jshell@9-internal/StopDetectingInputStream.java:64)