kernel.jar is a component in iText Java library to provide low-level functionalities. iText Java library allows you to generate and manage PDF documents.

The Source Code files are provided together with the JAR file in the binary packge like iText7-Core-7.1.4.zip. You can download it at iText 7 Core Download site.

You can compile it to generate your JAR file, using kernel.pom as the build configuration file.

The source code of kernel-7.1.4.jar is provided below:

⏎ com/itextpdf/kernel/xmp/PdfConst.java

/*

    This file is part of the iText (R) project.
    Copyright (c) 1998-2018 iText Group NV
    Authors: Bruno Lowagie, Paulo Soares, et al.

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU Affero General Public License version 3
    as published by the Free Software Foundation with the addition of the
    following permission added to Section 15 as permitted in Section 7(a):
    FOR ANY PART OF THE COVERED WORK IN WHICH THE COPYRIGHT IS OWNED BY
    ITEXT GROUP. ITEXT GROUP DISCLAIMS THE WARRANTY OF NON INFRINGEMENT
    OF THIRD PARTY RIGHTS

    This program is distributed in the hope that it will be useful, but
    WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
    or FITNESS FOR A PARTICULAR PURPOSE.
    See the GNU Affero General Public License for more details.
    You should have received a copy of the GNU Affero General Public License
    along with this program; if not, see http://www.gnu.org/licenses or write to
    the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
    Boston, MA, 02110-1301 USA, or download the license from the following URL:
    http://itextpdf.com/terms-of-use/

    The interactive user interfaces in modified source and object code versions
    of this program must display Appropriate Legal Notices, as required under
    Section 5 of the GNU Affero General Public License.

    In accordance with Section 7(b) of the GNU Affero General Public License,
    a covered work must retain the producer line in every PDF that is created
    or manipulated using iText.

    You can be released from the requirements of the license by purchasing
    a commercial license. Buying such a license is mandatory as soon as you
    develop commercial activities involving the iText software without
    disclosing the source code of your own applications.
    These activities include: offering paid services to customers as an ASP,
    serving PDFs on the fly in a web application, shipping iText with a closed
    source product.

    For more information, please contact iText Software Corp. at this
    address: sales@itextpdf.com
 */
package com.itextpdf.kernel.xmp;

/**
 * Class that contains several constants.
 */
public class PdfConst {
    /** External Contributors to the resource (other than the authors). */
    public static final String Contributor = "contributor";
    /** The extent or scope of the resource. */
    public static final String Coverage = "coverage";
    /** The authors of the resource (listed in order of precedence, if significant). */
    public static final String Creator = "creator";
    /** Date(s) that something interesting happened to the resource. */
    public static final String Date = "date";
    /** A textual description of the content of the resource. Multiple values may be present for different languages. */
    public static final String Description = "description";
    /** The file format used when saving the resource. Tools and applications should set this property to the save format of the data. It may include appropriate qualifiers. */
    public static final String Format = "format";
    /** An unordered array of text strings that unambiguously identify the resource within a given context. */
    public static final String Identifier = "identifier";
    /** An unordered array specifying the languages used in the	resource. */
    public static final String Language = "language";
    /** Publishers. */
    public static final String Publisher = "publisher";
    /** Relationships to other documents. */
    public static final String Relation = "relation";
    /** Informal rights statement, selected by language. */
    public static final String Rights = "rights";
    /** Unique identifier of the work from which this resource was derived. */
    public static final String Source = "source";
    /** An unordered array of descriptive phrases or keywords that specify the topic of the content of the resource. */
    public static final String Subject = "subject";
    /** The title of the document, or the name given to the resource. Typically, it will be a name by which the resource is formally known. */
    public static final String Title = "title";
    /** A document type; for example, novel, poem, or working paper. */
    public static final String Type = "type";
    /** Keywords. */
    public static final String Keywords = "Keywords";
    /** The PDF file version (for example: 1.0, 1.3, and so on). */
    public static final String Version = "PDFVersion";
    /** The Producer. */
    public static final String Producer = "Producer";
    /** The part */
    public static final String Part = "part";
    /** An unordered array specifying properties that were edited outside the authoring application. Each item should contain a single namespace and XPath separated by one ASCII space (U+0020). */
    public static final String Advisory = "Advisory";
    /** The base URL for relative URLs in the document content. If this document contains Internet links, and those links are relative, they are relative to this base URL. This property provides a standard way for embedded relative URLs to be interpreted by tools. Web authoring tools should set the value based on their notion of where URLs will be interpreted. */
    public static final String BaseURL = "BaseURL";
    /** The date and time the resource was originally created. */
    public static final String CreateDate = "CreateDate";
    /** The name of the first known tool used to create the resource. If history is present in the metadata, this value should be equivalent to that of xmpMM:History's softwareAgent property. */
    public static final String CreatorTool = "CreatorTool";
    /** The date and time that any metadata for this resource was last changed. */
    public static final String MetadataDate = "MetadataDate";
    /** The date and time the resource was last modified. */
    public static final String ModifyDate = "ModifyDate";
    /** A short informal name for the resource. */
    public static final String Nickname = "Nickname";
    /** An alternative array of thumbnail images for a file, which can differ in characteristics such as size or image encoding. */
    public static final String Thumbnails = "Thumbnails";
    /** Indicates whether the document has been modified to include trapping information */
    public static final String Trapped = "Trapped";

}

⏎ com/itextpdf/kernel/xmp/PdfConst.java

Or download all of them as a single archive file:

File name: kernel-7.1.4-sources.jar
File size: 1201221 bytes
Release date: 2018-10-09
Download 

⇒ iText io.jar Source Code

⇐ Download and Install iText7-Core-7.1.4.zip

⇑ Download and Install iText Java Library

⇑⇑ iText for PDF Generation