我们的中央银行以多种方式提供货币汇率。例如，一种日期货币很容易获得：http://api.nbp.pl/api/exchangerates/rates/a/usd/2020-08-20?format=json （它以简单大括号{作为典型的json开头）
但另一张表-每种货币的日期：http://api.nbp.pl/api/exchangerates/tables/a/2020-08-20?format=json 在代码行后返回“nullsession”

if (httpURLConnection.getResponseCode() == okRespCode) { ...

尽管这个json在webrowser中没有任何问题。它以方括号[作为数组]开始。
你见过并解决过这样的问题吗？
请从我的idempiere开发ide中找到以下异常堆栈跟踪。
pm org.compiere.process.svr进程严重：nullsession java.lang.nosuchfielderror:nullsession at sun.security.ssl.clienthandshaker.getkickstartmessage（clienthandshaker）。java:1343)在sun.security.ssl.handshaker.kickstart（握手器。java:1117)在sun.security.ssl.sslsocketimpl.kickstartshandshake（sslsocketimpl。java:1500)在sun.security.ssl.sslsocketimpl.performitialhandshake（sslsocketimpl。java:1367)在sun.security.ssl.sslsocketimpl.startAndShake（sslsocketimpl。java:1416)在sun.security.ssl.sslsocketimpl.startAndShake（sslsocketimpl。java:1400)在sun.net。www.protocol.https.httpsclient.afterconnect（httpsclient。java:559)在太阳网。www.protocol.https.abstractdelegatehttpsurlconnection.connect（abstractdelegatehttpsurlconnection。java:185)在sun.net。www.protocol.http.httpurlconnection.getinputstream0（httpurlconnection。java:1570)在sun.net。www.protocol.http.httpurlconnection.getinputstream（httpurlconnection。java:1498)在java.net.httpurlconnection.getresponsecode（httpurlconnection。java:480)在sun.net。www.protocol.https.httpsurlconnectionimpl.getresponsecode（httpsurlconnectionimpl。java:352)在one.stabilis.utils.jsonutils.readjsontostring（jsonutils。java:75)在one.stabilis.utils.jsonutils.readarrayofexchangeratestable（jsonutils。java:108)在一个.stabilis.utils.jsonutils.publishedondatetable（jsonutils。java:55)在one.stabilis.utils.jsonutils.getpublishedondatetable（jsonutils。java:32)在one.stabilis.impconvrates.importcurrencyrates.doit（importcurrencyrates。java:84)在org.compiere.process.svrprocess.process（svrprocess。java:201)在org.compiere.process.svrprocess.startprocess（svrprocess。java:147)在org.adempiere.util.processutil.startjavaprocess（processutil。java:172)在org.adempiere.util.processutil.startjavaprocess（processutil。java:139)在org.adempiere.util.processutil.startjavaprocess（processutil。java:128)在org.compiere.interfaces.impl.serverbean.process（serverbean。java:78)在org.compiere.apps.abstractprocessctl.startprocess（abstractprocessctl。java:429)在org.compiere.apps.abstractprocessctl.run（abstractprocessctl。java:234)在org.adempiere.webui.apps.wprocessctl.process（wprocessctl。java:197)在org.adempiere.webui.apps.abstractprocessdialog$processdialogrunnable.dorun（abstractprocessdialog。java:1083)在org.adempiere.util.contextrunnable.run（contextrunnable。java:38)在org.adempiere.webui.apps.desktoprunnable.run（desktoprunnable。java:40)在java.util.concurrent.executors$runnableadapter.call（executors。java:511)在java.util.concurrent.futuretask.run（futuretask。java:266)在java.util.concurrent.scheduledthreadpoolexecutor$scheduledfuturetask.access$201（scheduledthreadpoolexecutor。java:180)在java.util.concurrent.scheduledthreadpoolexecutor$scheduledfuturetask.run（scheduledthreadpoolexecutor。java:293)在java.util.concurrent.threadpoolexecutor.runworker（threadpoolexecutor。java:1149)在java.util.concurrent.threadpoolexecutor$worker.run（threadpoolexecutor。java:624)在java.lang.thread.run（线程。java:748)