[{"_1":2,"_3":-5,"_4":-5},"loaderData",{"_5":6,"_7":8},"actionData","errors","root",{"_29":-5,"_39":-5,"_40":41,"_42":43,"_44":45,"_46":47,"_48":49,"_50":51,"_52":53,"_54":55,"_56":57,"_58":59},"routes/_store+/_readers+/email_author.$slug/route",{"_9":10,"_11":-5,"_12":-5},"book",{"_13":14,"_15":16,"_17":18,"_19":20,"_21":22,"_23":24},"currentUser","formToken","id","Z2lkOi8vbGVhbnB1Yi9TdG9yZTo6Qm9va1Byb2R1Y3QvODQzMTE","title","The JasperReports Cookbook","state","published","contactAuthorMethod","email","aboutText","

Every recipe in this book answers a question that never got an accepted answer, and every claim in it was run before it was written. The recipes were selected from the JasperReports questions with at least 500 views and no resolution. Before a word was written, each question was put to a current chat model cold, the answer was taken apart claim by claim, and each falsifiable claim was run in a lab against the library itself. Of 113 unsettled questions graded that way, 82 drew an answer with at least one wrong claim, and 56 drew an answer with a claim that fails without saying so: the property is accepted and ignored, the element is legal in the wrong place, the exception you were told to expect never arrives. Those silent failures are what the book is for.

86 recipes in thirteen parts, ordered by what breaks first. The report that will not load and the four bytes in the cause chain that say why. Text that will not fit and space that will not close, down to the one pixel that decides whether an element floats. Expressions, parameters and variables. Subreports: the blank child and which of four things happened to it. Pages, breaks and the blank page that is not there. Styles, and the conditional style that paints nothing. Fonts and what the PDF actually contains. Groups and tables. Exporting to Excel, HTML, CSV and Word. Charts, and the customizer that compiles, runs and draws nothing. Datasources and beans. Memory and the virtualizer that does not bound it. The report query on four real database engines. Plus an appendix of every class that moved between 6.20.6 and 7.0.0, read off the jars.

Every recipe ends with a Status line naming the date, the fixture that produced the verdict and what was actually measured. If a claim was not run, the Status line says so in those words. The bench is pinned: JasperReports 6.20.6 on Temurin 21, with 6.17.0 and 7.0.0 beside it for portability claims. 127 pages, PDF. The fixtures themselves are the companion Lab Pack, available with the book at robcotek.com/jasper/.

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Kick off your book project, get started with GhostAI, get better at marketing, or spend the day doing all three! Free live workshops on Zoom. Saturday, June 27, 2026.

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