JRE 8 rt.jar is the JAR file for JRE 8 RT (Runtime) libraries. JRE (Java Runtime) 8 is the runtime environment included in JDK 8. JRE 8 rt.jar libraries are divided into 6 packages:

com.* - Internal Oracle and Sun Microsystems libraries
java.* - Standard Java API libraries.
javax.* - Extended Java API libraries.
jdk.* -  JDK supporting libraries.
org.* - Third party libraries.
sun.* - Old libraries developed by Sun Microsystems.

JAR File Information:

Directory of C:\fyicenter\jdk-1.8.0_191\jre\lib
      63,596,151 rt.jar

Here is the list of Java classes of the com.* package in JRE 1.8.0_191 rt.jar. Java source codes are also provided.

⏎ com/sun/java/swing/plaf/windows/resources/windows_pt_BR.java

package com.sun.java.swing.plaf.windows.resources;

import java.util.ListResourceBundle;

public final class windows_pt_BR extends ListResourceBundle {
    protected final Object[][] getContents() {
        return new Object[][] {
            { "FileChooser.detailsViewActionLabel.textAndMnemonic", "Detalhes" },
            { "FileChooser.detailsViewButtonAccessibleName", "Detalhes" },
            { "FileChooser.detailsViewButtonToolTip.textAndMnemonic", "Detalhes" },
            { "FileChooser.fileAttrHeader.textAndMnemonic", "Atributos" },
            { "FileChooser.fileDateHeader.textAndMnemonic", "Modificado" },
            { "FileChooser.fileNameHeader.textAndMnemonic", "Nome" },
            { "FileChooser.fileNameLabel.textAndMnemonic", "&Nome do arquivo:" },
            { "FileChooser.fileSizeHeader.textAndMnemonic", "Tamanho" },
            { "FileChooser.fileTypeHeader.textAndMnemonic", "Tipo" },
            { "FileChooser.filesOfTypeLabel.textAndMnemonic", "Arquivos do &tipo:" },
            { "FileChooser.folderNameLabel.textAndMnemonic", "&Nome da pasta:" },
            { "FileChooser.homeFolderAccessibleName", "In\u00EDcio" },
            { "FileChooser.homeFolderToolTip.textAndMnemonic", "In\u00EDcio" },
            { "FileChooser.listViewActionLabel.textAndMnemonic", "Lista" },
            { "FileChooser.listViewButtonAccessibleName", "Lista" },
            { "FileChooser.listViewButtonToolTip.textAndMnemonic", "Lista" },
            { "FileChooser.lookInLabel.textAndMnemonic", "Pesquisar &em:" },
            { "FileChooser.newFolderAccessibleName", "Nova Pasta" },
            { "FileChooser.newFolderActionLabel.textAndMnemonic", "Nova Pasta" },
            { "FileChooser.newFolderToolTip.textAndMnemonic", "Criar Nova Pasta" },
            { "FileChooser.refreshActionLabel.textAndMnemonic", "Atualizar" },
            { "FileChooser.saveInLabel.textAndMnemonic", "Salvar em:" },
            { "FileChooser.upFolderAccessibleName", "Acima" },
            { "FileChooser.upFolderToolTip.textAndMnemonic", "Um N\u00EDvel Acima" },
            { "FileChooser.viewMenuButtonAccessibleName", "Exibir Menu" },
            { "FileChooser.viewMenuButtonToolTipText", "Exibir Menu" },
            { "FileChooser.viewMenuLabel.textAndMnemonic", "Exibir" },
        };
    }
}

⏎ com/sun/java/swing/plaf/windows/resources/windows_pt_BR.java

Or download all of them as a single archive file:

File name: jre-rt-com-1.8.0_191-src.zip
File size: 8099783 bytes
Release date: 2018-10-28
Download 

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