pi4j doesn't compile with java 9

[bsutton]

I've just upgraded to java 9 and when trying to build pi4j got the following errors:

pi4j-core/src/main/java/com/pi4j/io/file/LinuxFile.java:[34,16] cannot find symbol
symbol: class Cleaner
location: package sun.misc
pi4j-core/src/main/java/com/pi4j/io/file/LinuxFile.java:[35,16] cannot find symbol
symbol: class SharedSecrets
location: package sun.misc
pi4j/pi4j-core/src/main/java/com/pi4j/io/file/LinuxFile.java:[215,32] cannot find symbol
symbol: variable SharedSecrets
location: class com.pi4j.io.file.LinuxFile
pi4j-core/src/main/java/com/pi4j/io/file/LinuxFile.java:[313,15] cannot find symbol
symbol: class Cleaner
location: class com.pi4j.io.file.LinuxFile

[albahrani]

With JDK9 access to the sun-packages has been restricted by default.
You may use the -jdkinternals flag when compiling to get it working without change right now.
On the long run the following should be done:

• Replace uses of sun.misc.Cleaner with java.lang.ref.Cleaner in LinuxFile.java
• Replace uses of sun.misc.SharedSecretswith jdk.internal.misc.SharedSecrets in LinuxFile.java

[pg-adm1n]

@albahrani There should be jdk.internal.ref.Cleaner instead of java.lang.ref.Cleaner

[agilkes]

In LinuxFile.java, I have replaced the "sun.misc" imports with imports of jdk.internal.misc.SharedSecrets and jdk.internal.ref.Cleaner. But when I "build" the pi4j.core project in Eclipse, the Java compiler (10.0.2) gives me "is not accessible" error messages for both imports. These result in 3 other compiler error messages that appear later in LinuxFile.java. How do you get the Java compile to succeed?

[pg-adm1n]

@agilkes You should add compiler parameters "--add-exports=java.base/jdk.internal.ref=ALL-UNNAMED --add-exports=java.base/jdk.internal.misc=ALL-UNNAMED"