Bug ID: JDK-8162492 JDK 9 javac still slower than JDK 8 for repeated compilation

Type: Bug
Component: tools
Sub-Component: javac
Affected Version: 9

Priority: P3
Status: Open
Resolution: Unresolved

Submitted: 2016-07-25
Updated: 2022-05-20

Versions (Unresolved/Resolved/Fixed)

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Other
tbd_minorUnresolved

Under JDK-8150641, performance of repeated compilation in JDK 9 was significantly improved. But it is still slower than in JDK 8, using the speedtest from JDK-8150641, using NetBeans 8.0 installation as the source of jar files:
---
SpeedTest.java-empty-shared
JDK 8
average compilation time: 7.1
vanilla JDK9
average compilation time: 24.975
SpeedTest.java-empty-unshared
JDK 8
average compilation time: 9.15
vanilla JDK9
average compilation time: 26.575
SpeedTest.java-jars-shared
JDK 8
average compilation time: 12.975
vanilla JDK9
average compilation time: 48.7
SpeedTest.java-jars-unshared
JDK 8
average compilation time: 133.6
vanilla JDK9
average compilation time: 353.175
---

Relates :	JDK-8150641 - Repeated compilation with a long classpath significantly slower on JDK 9
Relates :	JDK-8281316 - Compiler speed not scale with the number of jar files
Relates :	JDK-8171294 - Slow compilation with long classpaths under JDK 9