我正在使用JRebel在运行时进行代码替换。 所有类均已成功加载，但由于以下错误，一个类中只有一个字段失败。
2019-06-06 11:51:39 JRebel: ERROR Failed to initialize value for static field collegeID: java.lang.NullPointerException
at com.services.RetreiveCollegeService<clinit>(RetreiveCollegeService.java)
at com.services.RetreiveCollegeService.<clinit>(RetreiveCollegeService.java)
at sun.misc.Unsafe.ensureClassInitialized(Native Method)
at com.zeroturnaround.javarebel.gzo.a(SourceFile:52)
at com.zeroturnaround.javarebel.hau.a(SourceFile:33)
at com.zeroturnaround.javarebel.guk.a(SourceFile:35)
at com.zeroturnaround.reload.al.onClassEvent(SourceFile:97)
at com.zeroturnaround.javarebel.aw.b(SourceFile:170)
at com.zeroturnaround.javarebel.aw.a(SourceFile:141)
at com.zeroturnaround.javarebel.ap.a(SourceFile:86)
at com.zeroturnaround.javarebel.SDKReloaderImpl.d(SourceFile:74)
at com.zeroturnaround.javarebel.SDKReloaderImpl.c(SourceFile:65)
at com.zeroturnaround.javarebel.SDKReloaderImpl.fireReloadListeners(SourceFile:108)
at com.zeroturnaround.reload.ak.a(SourceFile:478)
at com.zeroturnaround.reload.b.m(SourceFile:507)
at com.zeroturnaround.reload.b.l(SourceFile:277)
at com.zeroturnaround.reload.b.k(SourceFile:58)
at com.zeroturnaround.reload.c.run(SourceFile:120)