The following error is thrown:

BW.Job-1 []: While executing [invoke] encountered [java.util.zip.ZipException] : [Not in GZIP format at java.util.zip.GZIPInputStream.readHeader(GZIPInputStream.java:165)]BW-JAVA-100001invokejava.util.zip.ZipExceptionNot in GZIP format at java.util.zip.GZIPInputStream.readHeader(GZIPInputStream.java:165). The error report is: Job-1 Error in [xx.process/yyy]
While executing [invoke] encountered [java.util.zip.ZipException] : [Not in GZIP format at java.util.zip.GZIPInputStream.readHeader(GZIPInputStream.java:165)]
    at com.tibco.plugin.java.JavaActivity.eval(Unknown Source)
    at com.tibco.pe.plugin.Activity.eval(Unknown Source)
    at com.tibco.pe.core.TaskImpl.eval(Unknown Source)
    at com.tibco.pe.core.Job.a(Unknown Source)
    at com.tibco.pe.core.Job.k(Unknown Source)
    at com.tibco.pe.core.JobDispatcher$JobCourier.a(Unknown Source)
    at com.tibco.pe.core.JobDispatcher$JobCourier.run(Unknown Source)

TIBCO BusinessWorks throws gzip error [java.util.zip.ZipException] : [Not in GZIP format at java.util.zip.GZIPInputStream.readHeader(GZIPInputStream.java:165)]when starting the engine.

TIBCO BusinessWorks 5.12

This is a property driven fix. The reason for this error is due to the data coming back on a SOAP Get Activity or HTTP call which is automatically decompressed. When the application is trying to again decompress the gzip data, the error is thrown. 

Add the property to the bwengine.tra file and redeploy the application.

bw.plugin.http.decompressGzipResponse=false