2. A detailed overview of the objects

 treeBuilder = {
    fobjTable: instance of java.util.HashMap(id=589)
    namespaces: instance of java.util.HashSet(id=590)
    currentFObj: null
    rootFObj: null
    foInputHandler: instance of org.apache.fop.fo.FOTreeHandler(id=591)
    userAgent: instance of org.apache.fop.apps.FOUserAgent(id=592)
    foTreeControl: instance of org.apache.fop.apps.Document(id=593)
    class$org$apache$fop$fo$ElementMapping: instance of java.lang.Class(reflected class=org.apache.fop.fo.ElementMapping, id=450)
}
 treeBuilder.foInputHandler = {
    collectStatistics: true
    MEM_PROFILE_WITH_GC: false
    runtime: instance of java.lang.Runtime(id=595)
    pageCount: 0
    initialMemory: 0
    startTime: 0
    foTreeListeners: instance of java.util.HashSet(id=596)
    org.apache.fop.fo.FOInputHandler.foTreeControl: instance of org.apache.fop.apps.Document(id=593)
    org.apache.avalon.framework.logger.AbstractLogEnabled.m_logger: instance of org.apache.avalon.framework.logger.ConsoleLogger(id=597)
}
 treeBuilder.foTreeControl = "org.apache.fop.apps.Document@125844f"
 treeBuilder.foInputHandler.foTreeListeners = "[org.apache.fop.apps.Document@125844f]"
 treeBuilder.userAgent = {
    log: instance of org.apache.avalon.framework.logger.ConsoleLogger(id=597)
    defaults: instance of java.util.HashMap(id=601)
    handlers: instance of java.util.HashMap(id=602)
    baseURL: ""
    pdfEncryptionParams: null
    px2mm: 0.35277778
}
 treeBuilder.foTreeControl = {
    driver: instance of org.apache.fop.apps.Driver(id=587)
    usedFonts: instance of java.util.HashMap(id=604)
    triplets: instance of java.util.HashMap(id=605)
    fonts: instance of java.util.HashMap(id=606)
    layoutStrategy: instance of org.apache.fop.layoutmgr.LayoutManagerLS(id=607)
    areaTree: instance of org.apache.fop.area.AreaTree(id=608)
    atModel: instance of org.apache.fop.area.RenderPagesModel(id=609)
    bookmarks: null
    idReferences: instance of java.util.HashSet(id=610)
    foInputHandler: instance of org.apache.fop.fo.FOTreeHandler(id=591)
}
 treeBuilder.foTreeControl.driver = {
    NOT_SET: 0
    RENDER_PDF: 1
    RENDER_AWT: 2
    RENDER_MIF: 3
    RENDER_XML: 4
    RENDER_PRINT: 5
    RENDER_PCL: 6
    RENDER_PS: 7
    RENDER_TXT: 8
    RENDER_SVG: 9
    RENDER_RTF: 10
    treeBuilder: instance of org.apache.fop.fo.FOTreeBuilder(id=588)
    rendererType: 1
    renderer: instance of org.apache.fop.render.pdf.PDFRenderer(id=599)
    foInputHandler: instance of org.apache.fop.fo.FOTreeHandler(id=591)
    source: null
    stream: instance of java.io.BufferedOutputStream(id=600)
    reader: null
    log: instance of org.apache.avalon.framework.logger.ConsoleLogger(id=597)
    userAgent: instance of org.apache.fop.apps.FOUserAgent(id=592)
    currentDocument: instance of org.apache.fop.apps.Document(id=593)
}
 treeBuilder.foTreeControl.areaTree = {
    model: instance of org.apache.fop.area.RenderPagesModel(id=609)
    atControl: instance of org.apache.fop.apps.Document(id=593)
    idLocations: instance of java.util.HashMap(id=615)
    resolve: instance of java.util.HashMap(id=616)
    treeExtensions: instance of java.util.ArrayList(id=617)
}
 treeBuilder.foTreeControl.atModel = {
    renderer: instance of org.apache.fop.render.pdf.PDFRenderer(id=599)
    prepared: instance of java.util.ArrayList(id=618)
    pendingExt: instance of java.util.ArrayList(id=619)
    endDocExt: instance of java.util.ArrayList(id=620)
    org.apache.fop.area.StorePagesModel.pageSequence: null
    org.apache.fop.area.StorePagesModel.titles: instance of java.util.ArrayList(id=621)
    org.apache.fop.area.StorePagesModel.currSequence: null
    org.apache.fop.area.StorePagesModel.extensions: instance of java.util.ArrayList(id=622)
}
 treeBuilder.foTreeControl.atModel.renderer = {
    MIME_TYPE: "application/pdf"
    pdfDoc: instance of org.apache.fop.pdf.PDFDocument(id=624)
    pages: null
    pageReferences: instance of java.util.HashMap(id=625)
    pvReferences: instance of java.util.HashMap(id=626)
    ostream: instance of java.io.BufferedOutputStream(id=600)
    pdfResources: null
    currentStream: null
    currentContext: null
    currentPage: null
    currentState: null
    currentFontName: ""
    currentFontSize: 0
    pageHeight: 0
    filterMap: null
    textOpen: false
    prevWordY: 0
    prevWordX: 0
    prevWordWidth: 0
    wordAreaPDF: instance of java.lang.StringBuffer(id=627)
    BPMarginOffset: 0
    IPMarginOffset: 0
    org.apache.fop.render.PrintRenderer.fontInfo: instance of org.apache.fop.apps.Document(id=593)
    org.apache.fop.render.PrintRenderer.fontList: null
    org.apache.fop.render.AbstractRenderer.userAgent: instance of org.apache.fop.apps.FOUserAgent(id=592)
    org.apache.fop.render.AbstractRenderer.producer: "FOP 1.0dev"
    org.apache.fop.render.AbstractRenderer.creator: null
    org.apache.fop.render.AbstractRenderer.creationDate: null
    org.apache.fop.render.AbstractRenderer.options: instance of java.util.HashMap(id=629)
    org.apache.fop.render.AbstractRenderer.currentBPPosition: 0
    org.apache.fop.render.AbstractRenderer.currentIPPosition: 0
    org.apache.fop.render.AbstractRenderer.currentBlockIPPosition: 0
    org.apache.fop.render.AbstractRenderer.containingBPPosition: 0
    org.apache.fop.render.AbstractRenderer.containingIPPosition: 0
    org.apache.avalon.framework.logger.AbstractLogEnabled.m_logger: instance of org.apache.avalon.framework.logger.ConsoleLogger(id=597)
}
 treeBuilder.foTreeControl.layoutStrategy = {
    name: "layoutmgr"
    addLMVisitor: null
    org.apache.fop.layout.LayoutStrategy.name: "undefined"
    org.apache.fop.layout.LayoutStrategy.document: instance of org.apache.fop.apps.Document(id=593)
}
 treeBuilder.foTreeControl.atModel.renderer.ostream = {
    buf: instance of byte[512] (id=632)
    count: 15
    java.io.FilterOutputStream.out: instance of java.io.FileOutputStream(id=633)
}

For the members fontList, fonts, usedFonts and triplets of treeBuilder.foTreeControl, see under Fonts.