Bug 202236 When select NULL value for multi-value parameter, cause NPE.
Description: When select NULL value for multi-value parameter, cause NPE. Build number: 2.2.1 Steps to reproduce: 1, New a list parameter, check Allow multi-value, uncheck isRequired 2, Select parameter data type as Date 3, Add some items into list 4, Preview 5, Select Null Value item in list Expected result: Can accept Null value for multi-value parameter Actual result: Cause NPE.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/api/impl/EngineTask.java
import org.eclipse.birt.report.engine.api.HTMLRenderContext;
import org.eclipse.birt.report.engine.api.HTMLRenderOption;
import org.eclipse.birt.report.engine.api.IEngineConfig;
import org.eclipse.birt.report.engine.api.IEngineTask;
import org.eclipse.birt.report.engine.api.IPDFRenderOption;
import org.eclipse.birt.report.engine.api.IRenderOption;
import org.eclipse.birt.report.engine.api.IReportEngine;
import org.eclipse.birt.report.engine.api.IReportRunnable;
import org.eclipse.birt.report.engine.api.PDFRenderContext;
import org.eclipse.birt.report.engine.api.PDFRenderOption;
import org.eclipse.birt.report.engine.api.RenderOption;
import org.eclipse.birt.report.engine.api.UnsupportedFormatException;
import org.eclipse.birt.report.engine.api.script.IReportContext;
import org.eclipse.birt.report.engine.emitter.EngineEmitterServices;
import org.eclipse.birt.report.engine.emitter.IContentEmitter;
import org.eclipse.birt.report.engine.executor.ExecutionContext;
import org.eclipse.birt.report.engine.executor.IReportExecutor;
import org.eclipse.birt.report.engine.extension.internal.ExtensionManager;
import org.eclipse.birt.report.engine.i18n.MessageConstants;
import org.eclipse.birt.report.engine.layout.IReportLayoutEngine;
import org.eclipse.birt.report.engine.layout.LayoutEngineFactory;
import org.eclipse.birt.report.engine.script.internal.ReportContextImpl;
import org.eclipse.birt.report.engine.script.internal.ReportScriptExecutor;
import org.eclipse.birt.report.model.api.CascadingParameterGroupHandle;
import org.eclipse.birt.report.model.api.DataSetHandle;
import org.eclipse.birt.report.model.api.IncludeScriptHandle;
import org.eclipse.birt.report.model.api.ParameterGroupHandle;
import org.eclipse.birt.report.model.api.ReportDesignHandle;
import org.eclipse.birt.report.model.api.ScalarParameterHandle;
import org.eclipse.birt.report.model.api.SlotHandle;