package org.kohsuke.github;

/**
 * A Content of a repository.
 *
 * @author Alexandre COLLIGNON
 */
public final class GHContent {
    private GHRepository owner;

    private String type;
    private String encoding;
    private long size;
    private String name;
    private String path;
    private String content;
    private String url; // this is the API url
    private String git_url;    // this is the Blob url
    private String html_url;    // this is the UI

    public GHRepository getOwner() {
        return owner;
    }

    public String getType() {
        return type;
    }

    public String getEncoding() {
        return encoding;
    }

    public long getSize() {
        return size;
    }

    public String getName() {
        return name;
    }

    public String getPath() {
        return path;
    }

    public String getContent() {
        return new String(javax.xml.bind.DatatypeConverter.parseBase64Binary(getEncodedContent()));
    }

    public String getEncodedContent() {
        return content;
    }

    public String getUrl() {
        return url;
    }

    public String getGitUrl() {
        return git_url;
    }

    public String getHtmlUrl() {
        return html_url;
    }

    public boolean isFile() {
        return "file".equals(type);
    }

    public boolean isDirectory() {
        return "dir".equals(type);
    }
}

package org.kohsuke.github;

/**
 * A Content of a repository.
 *
 * @author Alexandre COLLIGNON
 */
public final class GHContent {
    private GHRepository owner;

    private String type;
    private String encoding;
    private long size;
    private String sha;
    private String name;
    private String path;
    private String content;
    private String url; // this is the API url
    private String git_url;    // this is the Blob url
    private String html_url;    // this is the UI

    public GHRepository getOwner() {
        return owner;
    }

    public String getType() {
        return type;
    }

    public String getEncoding() {
        return encoding;
    }

    public long getSize() {
        return size;
    }

    public String getSha() {
        return sha;
    }

    public String getName() {
        return name;
    }

    public String getPath() {
        return path;
    }

    public String getContent() {
        return new String(javax.xml.bind.DatatypeConverter.parseBase64Binary(getEncodedContent()));
    }

    public String getEncodedContent() {
        return content;
    }

    public String getUrl() {
        return url;
    }

    public String getGitUrl() {
        return git_url;
    }

    public String getHtmlUrl() {
        return html_url;
    }

    public boolean isFile() {
        return "file".equals(type);
    }

    public boolean isDirectory() {
        return "dir".equals(type);
    }
}

Add the ability to retrieve the sha of the content.