hello how to fix unity error Win32Exception ?

Win32Exception: ApplicationName=‘C:\Program Files\Java\jdk-9.0.1\bin\java.exe’, CommandLine=‘-Xmx2048M -Dcom.android.sdkmanager.toolsdir=“C:/Android/sdk ools” -Dfile.encoding=UTF8 -jar “C:\Program Files\Unity\Editor\Data\PlaybackEngines\AndroidPlayer/Tools\sdktools.jar” -’, CurrentDirectory=‘C:\Android\alma’
System.Diagnostics.Process.Start_noshell (System.Diagnostics.ProcessStartInfo startInfo, System.Diagnostics.Process process)
System.Diagnostics.Process.Start_common (System.Diagnostics.ProcessStartInfo startInfo, System.Diagnostics.Process process)
System.Diagnostics.Process.Start ()
(wrapper remoting-invoke-with-check) System.Diagnostics.Process:Start ()
UnityEditor.Utils.Program.Start (System.EventHandler exitCallback) (at C:/buildslave/unity/build/Editor/Mono/Utils/Program.cs:44)
UnityEditor.Utils.Program.Start () (at C:/buildslave/unity/build/Editor/Mono/Utils/Program.cs:28)
UnityEditor.Android.Command.Run (System.Diagnostics.ProcessStartInfo psi, UnityEditor.Android.WaitingForProcessToExit waitingForProcessToExit, System.String errorMsg)
UnityEditor.Android.AndroidSDKTools.RunCommandInternal (System.String javaExe, System.String sdkToolsDir, System.String sdkToolCommand, Int32 memoryMB, System.String workingdir, UnityEditor.Android.WaitingForProcessToExit waitingForProcessToExit, System.String errorMsg)
UnityEditor.Android.AndroidSDKTools.RunCommandSafe (System.String javaExe, System.String sdkToolsDir, System.String sdkToolCommand, Int32 memoryMB, System.String workingdir, UnityEditor.Android.WaitingForProcessToExit waitingForProcessToExit, System.String errorMsg)
UnityEditor.Android.AndroidSDKTools.RunCommand (System.String sdkToolCommand, Int32 memoryMB, System.String workingdir, UnityEditor.Android.WaitingForProcessToExit waitingForProcessToExit, System.String errorMsg)
UnityEditor.Android.AndroidSDKTools.RunCommand (System.String sdkToolCommand, System.String workingdir, UnityEditor.Android.WaitingForProcessToExit waitingForProcessToExit, System.String errorMsg)
UnityEditor.Android.AndroidSDKTools.RunCommand (System.String sdkToolCommand, UnityEditor.Android.WaitingForProcessToExit waitingForProcessToExit, System.String errorMsg)
UnityEditor.Android.AndroidSDKTools.GetSDKBuildToolsDir ()
UnityEditor.Android.AndroidSDKTools.UpdateToolsDirectories ()
UnityEditor.Android.AndroidSDKTools…ctor (System.String sdkRoot)
UnityEditor.Android.AndroidSDKTools.GetInstance ()
UnityEditor.Android.PostProcessor.Tasks.CheckAndroidSDK.Execute (UnityEditor.Android.PostProcessor.PostProcessorContext context)
UnityEditor.Android.PostProcessor.PostProcessRunner.RunAllTasks (UnityEditor.Android.PostProcessor.PostProcessorContext context)
UnityEditor.Android.PostProcessAndroidPlayer.PrepareForBuild (BuildOptions options, BuildTarget target)
UnityEditor.Android.AndroidBuildPostprocessor.PrepareForBuild (BuildOptions options, BuildTarget target)
UnityEditor.PostprocessBuildPlayer.PrepareForBuild (BuildOptions options, BuildTargetGroup targetGroup, BuildTarget target) (at C:/buildslave/unity/build/Editor/Mono/BuildPipeline/PostprocessBuildPlayer.cs:87)

Unity is currently incompatible with JDK 9.0.1

https://forum.unity.com/threads/java-9-jdk-9-support-by-unity-android.499354/

Downgrade to JDK 8