6 files changed, 562 insertions, 442 deletions

diff --git a/application/CMakeLists.txt b/application/CMakeLists.txt
index 00d93595..100785f2 100644
--- a/application/CMakeLists.txt
+++ b/application/CMakeLists.txt
@@ -163,6 +163,8 @@ SET(MULTIMC_SOURCES
 	widgets/FocusLineEdit.h
 	widgets/IconLabel.cpp
 	widgets/IconLabel.h
+	widgets/JavaSettingsWidget.cpp
+	widgets/JavaSettingsWidget.h
 	widgets/LabeledToolButton.cpp
 	widgets/LabeledToolButton.h
 	widgets/LineSeparator.cpp
diff --git a/application/pages/InstanceSettingsPage.ui b/application/pages/InstanceSettingsPage.ui
index 60262b9a..0c180df3 100644
--- a/application/pages/InstanceSettingsPage.ui
+++ b/application/pages/InstanceSettingsPage.ui
@@ -7,7 +7,7 @@
     <x>0</x>
     <y>0</y>
     <width>553</width>
-    <height>583</height>
+    <height>522</height>
    </rect>
   </property>
   <layout class="QVBoxLayout" name="verticalLayout">
@@ -211,19 +211,6 @@
          </layout>
         </widget>
        </item>
-       <item>
-        <spacer name="verticalSpacerMinecraft">
-         <property name="orientation">
-          <enum>Qt::Vertical</enum>
-         </property>
-         <property name="sizeHint" stdset="0">
-          <size>
-           <width>0</width>
-           <height>0</height>
-          </size>
-         </property>
-        </spacer>
-       </item>
       </layout>
      </widget>
      <widget class="QWidget" name="javaTab">
diff --git a/application/setupwizard/JavaWizardPage.cpp b/application/setupwizard/JavaWizardPage.cpp
index deeb5ffe..cd2bca46 100644
--- a/application/setupwizard/JavaWizardPage.cpp
+++ b/application/setupwizard/JavaWizardPage.cpp
@@ -17,184 +17,35 @@
 #include <sys.h>
 #include <QFileDialog>
 #include <JavaCommon.h>
+#include "widgets/JavaSettingsWidget.h"
 
 
 JavaWizardPage::JavaWizardPage(QWidget *parent)
 	:BaseWizardPage(parent)
 {
-	m_availableMemory = Sys::getSystemRam() / Sys::megabyte;
-
-	goodIcon = MMC->getThemedIcon("status-good");
-	yellowIcon = MMC->getThemedIcon("status-yellow");
-	badIcon = MMC->getThemedIcon("status-bad");
 	setupUi();
-
-	connect(m_minMemSpinBox, SIGNAL(valueChanged(int)), this, SLOT(memoryValueChanged(int)));
-	connect(m_maxMemSpinBox, SIGNAL(valueChanged(int)), this, SLOT(memoryValueChanged(int)));
-	connect(m_permGenSpinBox, SIGNAL(valueChanged(int)), this, SLOT(memoryValueChanged(int)));
-	connect(m_versionWidget, &VersionSelectWidget::selectedVersionChanged, this, &JavaWizardPage::javaVersionSelected);
-	connect(m_javaBrowseBtn, &QPushButton::clicked, this, &JavaWizardPage::on_javaBrowseBtn_clicked);
-	connect(m_javaPathTextBox, &QLineEdit::textEdited, this, &JavaWizardPage::javaPathEdited);
-	connect(m_javaStatusBtn, &QToolButton::clicked, this, &JavaWizardPage::on_javaStatusBtn_clicked);
 }
 
 void JavaWizardPage::setupUi()
 {
 	setObjectName(QStringLiteral("javaPage"));
-	m_verticalLayout = new QVBoxLayout(this);
-	m_verticalLayout->setObjectName(QStringLiteral("verticalLayout"));
-
-	m_versionWidget = new VersionSelectWidget(MMC->javalist().get(), this);
-	m_versionWidget->setResizeOn(2);
-	m_verticalLayout->addWidget(m_versionWidget);
-
-	m_horizontalLayout = new QHBoxLayout();
-	m_horizontalLayout->setObjectName(QStringLiteral("horizontalLayout"));
-	m_javaPathTextBox = new QLineEdit(this);
-	m_javaPathTextBox->setObjectName(QStringLiteral("javaPathTextBox"));
-
-	m_horizontalLayout->addWidget(m_javaPathTextBox);
-
-	m_javaBrowseBtn = new QPushButton(this);
-	m_javaBrowseBtn->setObjectName(QStringLiteral("javaBrowseBtn"));
-	/*
-	QSizePolicy sizePolicy2(QSizePolicy::Fixed, QSizePolicy::Fixed);
-	sizePolicy2.setHorizontalStretch(0);
-	sizePolicy2.setVerticalStretch(0);
-	sizePolicy2.setHeightForWidth(m_javaBrowseBtn->sizePolicy().hasHeightForWidth());
-	m_javaBrowseBtn->setSizePolicy(sizePolicy2);
-	m_javaBrowseBtn->setMaximumSize(QSize(28, 16777215));
-	*/
-	m_horizontalLayout->addWidget(m_javaBrowseBtn);
-
-	m_javaStatusBtn = new QToolButton(this);
-	m_javaStatusBtn->setIcon(yellowIcon);
-	m_horizontalLayout->addWidget(m_javaStatusBtn);
-
-	m_verticalLayout->addLayout(m_horizontalLayout);
-
-	m_memoryGroupBox = new QGroupBox(this);
-	m_memoryGroupBox->setObjectName(QStringLiteral("memoryGroupBox"));
-	m_gridLayout_2 = new QGridLayout(m_memoryGroupBox);
-	m_gridLayout_2->setObjectName(QStringLiteral("gridLayout_2"));
-
-	m_labelMinMem = new QLabel(m_memoryGroupBox);
-	m_labelMinMem->setObjectName(QStringLiteral("labelMinMem"));
-	m_gridLayout_2->addWidget(m_labelMinMem, 0, 0, 1, 1);
-
-	m_minMemSpinBox = new QSpinBox(m_memoryGroupBox);
-	m_minMemSpinBox->setObjectName(QStringLiteral("minMemSpinBox"));
-	m_minMemSpinBox->setSuffix(QStringLiteral(" MB"));
-	m_minMemSpinBox->setMinimum(128);
-	m_minMemSpinBox->setMaximum(m_availableMemory);
-	m_minMemSpinBox->setSingleStep(128);
-	m_labelMinMem->setBuddy(m_minMemSpinBox);
-	m_gridLayout_2->addWidget(m_minMemSpinBox, 0, 1, 1, 1);
-
-	m_labelMaxMem = new QLabel(m_memoryGroupBox);
-	m_labelMaxMem->setObjectName(QStringLiteral("labelMaxMem"));
-	m_gridLayout_2->addWidget(m_labelMaxMem, 1, 0, 1, 1);
-
-	m_maxMemSpinBox = new QSpinBox(m_memoryGroupBox);
-	m_maxMemSpinBox->setObjectName(QStringLiteral("maxMemSpinBox"));
-	m_maxMemSpinBox->setSuffix(QStringLiteral(" MB"));
-	m_maxMemSpinBox->setMinimum(128);
-	m_maxMemSpinBox->setMaximum(m_availableMemory);
-	m_maxMemSpinBox->setSingleStep(128);
-	m_labelMaxMem->setBuddy(m_maxMemSpinBox);
-	m_gridLayout_2->addWidget(m_maxMemSpinBox, 1, 1, 1, 1);
+	QVBoxLayout * layout = new QVBoxLayout(this);
 
-	m_labelPermGen = new QLabel(m_memoryGroupBox);
-	m_labelPermGen->setObjectName(QStringLiteral("labelPermGen"));
-	m_labelPermGen->setText(QStringLiteral("PermGen:"));
-	m_gridLayout_2->addWidget(m_labelPermGen, 2, 0, 1, 1);
-	m_labelPermGen->setVisible(false);
-
-	m_permGenSpinBox = new QSpinBox(m_memoryGroupBox);
-	m_permGenSpinBox->setObjectName(QStringLiteral("permGenSpinBox"));
-	m_permGenSpinBox->setSuffix(QStringLiteral(" MB"));
-	m_permGenSpinBox->setMinimum(64);
-	m_permGenSpinBox->setMaximum(m_availableMemory);
-	m_permGenSpinBox->setSingleStep(8);
-	m_gridLayout_2->addWidget(m_permGenSpinBox, 2, 1, 1, 1);
-	m_permGenSpinBox->setVisible(false);
-
-	m_verticalLayout->addWidget(m_memoryGroupBox);
+	m_java_widget = new JavaSettingsWidget(this);
+	layout->addWidget(m_java_widget);
+	setLayout(layout);
 
 	retranslate();
 }
 
 void JavaWizardPage::refresh()
 {
-	m_versionWidget->loadList();
+	m_java_widget->refresh();
 }
 
 void JavaWizardPage::initializePage()
 {
-	m_versionWidget->initialize();
-	auto s = MMC->settings();
-	// Memory
-	observedMinMemory = s->get("MinMemAlloc").toInt();
-	observedMaxMemory = s->get("MaxMemAlloc").toInt();
-	observedPermGenMemory = s->get("PermGen").toInt();
-	m_minMemSpinBox->setValue(observedMinMemory);
-	m_maxMemSpinBox->setValue(observedMaxMemory);
-	m_permGenSpinBox->setValue(observedPermGenMemory);
-}
-
-bool JavaWizardPage::validatePage()
-{
-	auto settings = MMC->settings();
-	auto path = m_javaPathTextBox->text();
-	switch(javaStatus)
-	{
-		case JavaStatus::NotSet:
-		case JavaStatus::DoesNotExist:
-		case JavaStatus::DoesNotStart:
-		case JavaStatus::ReturnedInvalidData:
-		{
-			int button = CustomMessageBox::selectable(
-				this,
-				tr("No Java version selected"),
-				tr("You didn't select a Java version or selected something that doesn't work.\n"
-					"MultiMC will not be able to start Minecraft.\n"
-					"Do you wish to proceed without any Java?"
-					"\n\n"
-					"You can change the Java version in the settings later.\n"
-				),
-				QMessageBox::Warning,
-				QMessageBox::Yes | QMessageBox::No,
-				QMessageBox::NoButton
-			)->exec();
-			if(button == QMessageBox::No)
-			{
-				return false;
-			}
-		}
-		break;
-		case JavaStatus::Pending:
-		{
-			return false;
-		}
-		case JavaStatus::Good:
-		{
-			settings->set("JavaPath", path);
-		}
-	}
-
-	// Memory
-	auto s = MMC->settings();
-	s->set("MinMemAlloc", m_minMemSpinBox->value());
-	s->set("MaxMemAlloc", m_maxMemSpinBox->value());
-	if (m_permGenSpinBox->isVisible())
-	{
-		s->set("PermGen", m_permGenSpinBox->value());
-	}
-	else
-	{
-		s->reset("PermGen");
-	}
-	return true;
+	m_java_widget->initialize();
 }
 
 bool JavaWizardPage::wantsRefreshButton()
@@ -202,221 +53,37 @@ bool JavaWizardPage::wantsRefreshButton()
 	return true;
 }
 
-void JavaWizardPage::memoryValueChanged(int)
+bool JavaWizardPage::validatePage()
 {
-	bool actuallyChanged = false;
-	int min = m_minMemSpinBox->value();
-	int max = m_maxMemSpinBox->value();
-	int permgen = m_permGenSpinBox->value();
-	QObject *obj = sender();
-	if (obj == m_minMemSpinBox && min != observedMinMemory)
+	auto settings = MMC->settings();
+	auto result = m_java_widget->validate();
+	switch(result)
 	{
-		observedMinMemory = min;
-		actuallyChanged = true;
-		if (min > max)
+		default:
+		case JavaSettingsWidget::ValidationStatus::Bad:
 		{
-			observedMaxMemory = min;
-			m_maxMemSpinBox->setValue(min);
+			return false;
 		}
-	}
-	else if (obj == m_maxMemSpinBox && max != observedMaxMemory)
-	{
-		observedMaxMemory = max;
-		actuallyChanged = true;
-		if (min > max)
+		case JavaSettingsWidget::ValidationStatus::AllOK:
 		{
-			observedMinMemory = max;
-			m_minMemSpinBox->setValue(max);
+			settings->set("JavaPath", m_java_widget->javaPath());
 		}
-	}
-	else if (obj == m_permGenSpinBox && permgen != observedPermGenMemory)
-	{
-		observedPermGenMemory = permgen;
-		actuallyChanged = true;
-	}
-	if(actuallyChanged)
-	{
-		checkJavaPathOnEdit(m_javaPathTextBox->text());
-	}
-}
-
-void JavaWizardPage::javaVersionSelected(BaseVersionPtr version)
-{
-	auto java = std::dynamic_pointer_cast<JavaInstall>(version);
-	if(!java)
-	{
-		return;
-	}
-	auto visible = java->id.requiresPermGen();
-	m_labelPermGen->setVisible(visible);
-	m_permGenSpinBox->setVisible(visible);
-	m_javaPathTextBox->setText(java->path);
-	checkJavaPath(java->path);
-}
-
-void JavaWizardPage::on_javaBrowseBtn_clicked()
-{
-	QString filter;
-#if defined Q_OS_WIN32
-	filter = "Java (javaw.exe)";
-#else
-	filter = "Java (java)";
-#endif
-	QString raw_path = QFileDialog::getOpenFileName(this, tr("Find Java executable"), QString(), filter);
-	if(raw_path.isEmpty())
-	{
-		return;
-	}
-	QString cooked_path = FS::NormalizePath(raw_path);
-	m_javaPathTextBox->setText(cooked_path);
-	checkJavaPath(cooked_path);
-}
-
-void JavaWizardPage::on_javaStatusBtn_clicked()
-{
-	QString text;
-	bool failed = false;
-	switch(javaStatus)
-	{
-		case JavaStatus::NotSet:
-			checkJavaPath(m_javaPathTextBox->text());
-			return;
-		case JavaStatus::DoesNotExist:
-			text += QObject::tr("The specified file either doesn't exist or is not a proper executable.");
-			failed = true;
-			break;
-		case JavaStatus::DoesNotStart:
+		case JavaSettingsWidget::ValidationStatus::JavaBad:
 		{
-			text += QObject::tr("The specified java binary didn't start properly.<br />");
-			auto htmlError = m_result.errorLog;
-			if(!htmlError.isEmpty())
+			// Memory
+			auto s = MMC->settings();
+			s->set("MinMemAlloc", m_java_widget->minHeapSize());
+			s->set("MaxMemAlloc", m_java_widget->maxHeapSize());
+			if (m_java_widget->permGenEnabled())
 			{
-				htmlError.replace('\n', "<br />");
-				text += QString("<font color=\"red\">%1</font>").arg(htmlError);
+				s->set("PermGen", m_java_widget->permGenSize());
 			}
-			failed = true;
-			break;
-		}
-		case JavaStatus::ReturnedInvalidData:
-		{
-			text += QObject::tr("The specified java binary returned unexpected results:<br />");
-			auto htmlOut = m_result.outLog;
-			if(!htmlOut.isEmpty())
+			else
 			{
-				htmlOut.replace('\n', "<br />");
-				text += QString("<font color=\"red\">%1</font>").arg(htmlOut);
+				s->reset("PermGen");
 			}
-			failed = true;
-			break;
-		}
-		case JavaStatus::Good:
-			text += QObject::tr("Java test succeeded!<br />Platform reported: %1<br />Java version "
-				"reported: %2<br />").arg(m_result.realPlatform, m_result.javaVersion.toString());
-			break;
-		case JavaStatus::Pending:
-			// TODO: abort here?
-			return;
-	}
-	CustomMessageBox::selectable(
-		this,
-		failed ? QObject::tr("Java test success") : QObject::tr("Java test failure"),
-		text,
-		failed ? QMessageBox::Critical : QMessageBox::Information
-	)->show();
-}
-
-void JavaWizardPage::setJavaStatus(JavaWizardPage::JavaStatus status)
-{
-	javaStatus = status;
-	switch(javaStatus)
-	{
-		case JavaStatus::Good:
-			m_javaStatusBtn->setIcon(goodIcon);
-			break;
-		case JavaStatus::NotSet:
-		case JavaStatus::Pending:
-			m_javaStatusBtn->setIcon(yellowIcon);
-			break;
-		default:
-			m_javaStatusBtn->setIcon(badIcon);
-			break;
-	}
-}
-
-void JavaWizardPage::javaPathEdited(const QString& path)
-{
-	checkJavaPathOnEdit(path);
-}
-
-void JavaWizardPage::checkJavaPathOnEdit(const QString& path)
-{
-	auto realPath = FS::ResolveExecutable(path);
-	QFileInfo pathInfo(realPath);
-	if (pathInfo.baseName().toLower().contains("java"))
-	{
-		checkJavaPath(path);
-	}
-	else
-	{
-		if(!m_checker)
-		{
-			setJavaStatus(JavaStatus::NotSet);
-		}
-	}
-}
-
-void JavaWizardPage::checkJavaPath(const QString &path)
-{
-	if(m_checker)
-	{
-		queuedCheck = path;
-		return;
-	}
-	auto realPath = FS::ResolveExecutable(path);
-	if(realPath.isNull())
-	{
-		setJavaStatus(JavaStatus::DoesNotExist);
-		return;
-	}
-	setJavaStatus(JavaStatus::Pending);
-	m_checker.reset(new JavaChecker());
-	m_checker->m_path = path;
-	m_checker->m_minMem = m_minMemSpinBox->value();
-	m_checker->m_maxMem = m_maxMemSpinBox->value();
-	if(m_permGenSpinBox->isVisible())
-	{
-		m_checker->m_permGen = m_permGenSpinBox->value();
-	}
-	connect(m_checker.get(), &JavaChecker::checkFinished, this, &JavaWizardPage::checkFinished);
-	m_checker->performCheck();
-}
-
-void JavaWizardPage::checkFinished(JavaCheckResult result)
-{
-	m_result = result;
-	switch(result.validity)
-	{
-		case JavaCheckResult::Validity::Valid:
-		{
-			setJavaStatus(JavaStatus::Good);
-			break;
+			return true;
 		}
-		case JavaCheckResult::Validity::ReturnedInvalidData:
-		{
-			setJavaStatus(JavaStatus::ReturnedInvalidData);
-			break;
-		}
-		case JavaCheckResult::Validity::Errored:
-		{
-			setJavaStatus(JavaStatus::DoesNotStart);
-			break;
-		}
-	}
-	m_checker.reset();
-	if(!queuedCheck.isNull())
-	{
-		checkJavaPath(queuedCheck);
-		queuedCheck.clear();
 	}
 }
 
@@ -425,11 +92,5 @@ void JavaWizardPage::retranslate()
 	setTitle(tr("Java"));
 	setSubTitle(tr("You do not have a working Java set up yet or it went missing.\n"
 		"Please select one of the following or browse for a java executable."));
-	m_memoryGroupBox->setTitle(tr("Memory"));
-	m_maxMemSpinBox->setToolTip(tr("The maximum amount of memory Minecraft is allowed to use."));
-	m_labelMinMem->setText(tr("Minimum memory allocation:"));
-	m_labelMaxMem->setText(tr("Maximum memory allocation:"));
-	m_minMemSpinBox->setToolTip(tr("The amount of memory Minecraft is started with."));
-	m_permGenSpinBox->setToolTip(tr("The amount of memory available to store loaded Java classes."));
-	m_javaBrowseBtn->setText(tr("Browse"));
+	m_java_widget->retranslate();
 }
diff --git a/application/setupwizard/JavaWizardPage.h b/application/setupwizard/JavaWizardPage.h
index f240217e..4ea31d24 100644
--- a/application/setupwizard/JavaWizardPage.h
+++ b/application/setupwizard/JavaWizardPage.h
@@ -1,21 +1,8 @@
 #pragma once
 
 #include "BaseWizardPage.h"
-#include <BaseVersion.h>
-#include <QObjectPtr.h>
-#include <java/JavaChecker.h>
-#include <QIcon>
 
-class QLineEdit;
-class VersionSelectWidget;
-class QSpinBox;
-class QPushButton;
-class QVBoxLayout;
-class QHBoxLayout;
-class QGroupBox;
-class QGridLayout;
-class QLabel;
-class QToolButton;
+class JavaSettingsWidget;
 
 class JavaWizardPage : public BaseWizardPage
 {
@@ -32,58 +19,11 @@ public:
 	void initializePage() override;
 	bool validatePage() override;
 
-	enum class JavaStatus
-	{
-		NotSet,
-		Pending,
-		Good,
-		DoesNotExist,
-		DoesNotStart,
-		ReturnedInvalidData
-	} javaStatus = JavaStatus::NotSet;
-
-protected slots:
-	void memoryValueChanged(int);
-	void javaPathEdited(const QString &path);
-	void javaVersionSelected(BaseVersionPtr version);
-	void on_javaBrowseBtn_clicked();
-	void on_javaStatusBtn_clicked();
-	void checkFinished(JavaCheckResult result);
-
 protected: /* methods */
-	void checkJavaPathOnEdit(const QString &path);
-	void checkJavaPath(const QString &path);
-	void setJavaStatus(JavaStatus status);
 	void setupUi();
 	void retranslate() override;
 
 private: /* data */
-	VersionSelectWidget *m_versionWidget = nullptr;
-	QVBoxLayout *m_verticalLayout = nullptr;
-
-	QLineEdit * m_javaPathTextBox = nullptr;
-	QPushButton * m_javaBrowseBtn = nullptr;
-	QToolButton * m_javaStatusBtn = nullptr;
-	QHBoxLayout *m_horizontalLayout = nullptr;
-
-	QGroupBox *m_memoryGroupBox = nullptr;
-	QGridLayout *m_gridLayout_2 = nullptr;
-	QSpinBox *m_maxMemSpinBox = nullptr;
-	QLabel *m_labelMinMem = nullptr;
-	QLabel *m_labelMaxMem = nullptr;
-	QSpinBox *m_minMemSpinBox = nullptr;
-	QLabel *m_labelPermGen = nullptr;
-	QSpinBox *m_permGenSpinBox = nullptr;
-	QIcon goodIcon;
-	QIcon yellowIcon;
-	QIcon badIcon;
-
-	int observedMinMemory = 0;
-	int observedMaxMemory = 0;
-	int observedPermGenMemory = 0;
-	QString queuedCheck;
-	uint64_t m_availableMemory = 0ull;
-	shared_qobject_ptr<JavaChecker> m_checker;
-	JavaCheckResult m_result;
+	JavaSettingsWidget *m_java_widget = nullptr;
 };
 
diff --git a/application/widgets/JavaSettingsWidget.cpp b/application/widgets/JavaSettingsWidget.cpp
new file mode 100644
index 00000000..13cd27e7
--- /dev/null
+++ b/application/widgets/JavaSettingsWidget.cpp
@@ -0,0 +1,428 @@
+#include "JavaSettingsWidget.h"
+#include <MultiMC.h>
+
+#include <java/JavaInstall.h>
+#include <dialogs/CustomMessageBox.h>
+#include <java/JavaUtils.h>
+#include <sys.h>
+
+#include <QVBoxLayout>
+#include <QGroupBox>
+#include <QSpinBox>
+#include <QLabel>
+#include <QLineEdit>
+#include <QPushButton>
+#include <QToolButton>
+#include <widgets/VersionSelectWidget.h>
+#include <FileSystem.h>
+#include <QFileDialog>
+
+JavaSettingsWidget::JavaSettingsWidget(QWidget* parent) : QWidget(parent)
+{
+	m_availableMemory = Sys::getSystemRam() / Sys::megabyte;
+
+	goodIcon = MMC->getThemedIcon("status-good");
+	yellowIcon = MMC->getThemedIcon("status-yellow");
+	badIcon = MMC->getThemedIcon("status-bad");
+	setupUi();
+
+	connect(m_minMemSpinBox, SIGNAL(valueChanged(int)), this, SLOT(memoryValueChanged(int)));
+	connect(m_maxMemSpinBox, SIGNAL(valueChanged(int)), this, SLOT(memoryValueChanged(int)));
+	connect(m_permGenSpinBox, SIGNAL(valueChanged(int)), this, SLOT(memoryValueChanged(int)));
+	connect(m_versionWidget, &VersionSelectWidget::selectedVersionChanged, this, &JavaSettingsWidget::javaVersionSelected);
+	connect(m_javaBrowseBtn, &QPushButton::clicked, this, &JavaSettingsWidget::on_javaBrowseBtn_clicked);
+	connect(m_javaPathTextBox, &QLineEdit::textEdited, this, &JavaSettingsWidget::javaPathEdited);
+	connect(m_javaStatusBtn, &QToolButton::clicked, this, &JavaSettingsWidget::on_javaStatusBtn_clicked);
+}
+
+void JavaSettingsWidget::setupUi()
+{
+	setObjectName(QStringLiteral("javaSettingsWidget"));
+	m_verticalLayout = new QVBoxLayout(this);
+	m_verticalLayout->setObjectName(QStringLiteral("verticalLayout"));
+
+	m_versionWidget = new VersionSelectWidget(MMC->javalist().get(), this);
+	m_versionWidget->setResizeOn(2);
+	m_verticalLayout->addWidget(m_versionWidget);
+
+	m_horizontalLayout = new QHBoxLayout();
+	m_horizontalLayout->setObjectName(QStringLiteral("horizontalLayout"));
+	m_javaPathTextBox = new QLineEdit(this);
+	m_javaPathTextBox->setObjectName(QStringLiteral("javaPathTextBox"));
+
+	m_horizontalLayout->addWidget(m_javaPathTextBox);
+
+	m_javaBrowseBtn = new QPushButton(this);
+	m_javaBrowseBtn->setObjectName(QStringLiteral("javaBrowseBtn"));
+
+	m_horizontalLayout->addWidget(m_javaBrowseBtn);
+
+	m_javaStatusBtn = new QToolButton(this);
+	m_javaStatusBtn->setIcon(yellowIcon);
+	m_horizontalLayout->addWidget(m_javaStatusBtn);
+
+	m_verticalLayout->addLayout(m_horizontalLayout);
+
+	m_memoryGroupBox = new QGroupBox(this);
+	m_memoryGroupBox->setObjectName(QStringLiteral("memoryGroupBox"));
+	m_gridLayout_2 = new QGridLayout(m_memoryGroupBox);
+	m_gridLayout_2->setObjectName(QStringLiteral("gridLayout_2"));
+
+	m_labelMinMem = new QLabel(m_memoryGroupBox);
+	m_labelMinMem->setObjectName(QStringLiteral("labelMinMem"));
+	m_gridLayout_2->addWidget(m_labelMinMem, 0, 0, 1, 1);
+
+	m_minMemSpinBox = new QSpinBox(m_memoryGroupBox);
+	m_minMemSpinBox->setObjectName(QStringLiteral("minMemSpinBox"));
+	m_minMemSpinBox->setSuffix(QStringLiteral(" MB"));
+	m_minMemSpinBox->setMinimum(128);
+	m_minMemSpinBox->setMaximum(m_availableMemory);
+	m_minMemSpinBox->setSingleStep(128);
+	m_labelMinMem->setBuddy(m_minMemSpinBox);
+	m_gridLayout_2->addWidget(m_minMemSpinBox, 0, 1, 1, 1);
+
+	m_labelMaxMem = new QLabel(m_memoryGroupBox);
+	m_labelMaxMem->setObjectName(QStringLiteral("labelMaxMem"));
+	m_gridLayout_2->addWidget(m_labelMaxMem, 1, 0, 1, 1);
+
+	m_maxMemSpinBox = new QSpinBox(m_memoryGroupBox);
+	m_maxMemSpinBox->setObjectName(QStringLiteral("maxMemSpinBox"));
+	m_maxMemSpinBox->setSuffix(QStringLiteral(" MB"));
+	m_maxMemSpinBox->setMinimum(128);
+	m_maxMemSpinBox->setMaximum(m_availableMemory);
+	m_maxMemSpinBox->setSingleStep(128);
+	m_labelMaxMem->setBuddy(m_maxMemSpinBox);
+	m_gridLayout_2->addWidget(m_maxMemSpinBox, 1, 1, 1, 1);
+
+	m_labelPermGen = new QLabel(m_memoryGroupBox);
+	m_labelPermGen->setObjectName(QStringLiteral("labelPermGen"));
+	m_labelPermGen->setText(QStringLiteral("PermGen:"));
+	m_gridLayout_2->addWidget(m_labelPermGen, 2, 0, 1, 1);
+	m_labelPermGen->setVisible(false);
+
+	m_permGenSpinBox = new QSpinBox(m_memoryGroupBox);
+	m_permGenSpinBox->setObjectName(QStringLiteral("permGenSpinBox"));
+	m_permGenSpinBox->setSuffix(QStringLiteral(" MB"));
+	m_permGenSpinBox->setMinimum(64);
+	m_permGenSpinBox->setMaximum(m_availableMemory);
+	m_permGenSpinBox->setSingleStep(8);
+	m_gridLayout_2->addWidget(m_permGenSpinBox, 2, 1, 1, 1);
+	m_permGenSpinBox->setVisible(false);
+
+	m_verticalLayout->addWidget(m_memoryGroupBox);
+
+	retranslate();
+}
+
+void JavaSettingsWidget::initialize()
+{
+	m_versionWidget->initialize();
+	auto s = MMC->settings();
+	// Memory
+	observedMinMemory = s->get("MinMemAlloc").toInt();
+	observedMaxMemory = s->get("MaxMemAlloc").toInt();
+	observedPermGenMemory = s->get("PermGen").toInt();
+	m_minMemSpinBox->setValue(observedMinMemory);
+	m_maxMemSpinBox->setValue(observedMaxMemory);
+	m_permGenSpinBox->setValue(observedPermGenMemory);
+}
+
+void JavaSettingsWidget::refresh()
+{
+	m_versionWidget->loadList();
+}
+
+JavaSettingsWidget::ValidationStatus JavaSettingsWidget::validate()
+{
+	switch(javaStatus)
+	{
+		default:
+		case JavaStatus::NotSet:
+		case JavaStatus::DoesNotExist:
+		case JavaStatus::DoesNotStart:
+		case JavaStatus::ReturnedInvalidData:
+		{
+			int button = CustomMessageBox::selectable(
+				this,
+				tr("No Java version selected"),
+				tr("You didn't select a Java version or selected something that doesn't work.\n"
+					"MultiMC will not be able to start Minecraft.\n"
+					"Do you wish to proceed without any Java?"
+					"\n\n"
+					"You can change the Java version in the settings later.\n"
+				),
+				QMessageBox::Warning,
+				QMessageBox::Yes | QMessageBox::No,
+				QMessageBox::NoButton
+			)->exec();
+			if(button == QMessageBox::No)
+			{
+				return ValidationStatus::Bad;
+			}
+			return ValidationStatus::JavaBad;
+		}
+		break;
+		case JavaStatus::Pending:
+		{
+			return ValidationStatus::Bad;
+		}
+		case JavaStatus::Good:
+		{
+			return ValidationStatus::AllOK;
+		}
+	}
+}
+
+QString JavaSettingsWidget::javaPath() const
+{
+	return m_javaPathTextBox->text();
+}
+
+int JavaSettingsWidget::maxHeapSize() const
+{
+	return m_maxMemSpinBox->value();
+}
+
+int JavaSettingsWidget::minHeapSize() const
+{
+	return m_minMemSpinBox->value();
+}
+
+bool JavaSettingsWidget::permGenEnabled() const
+{
+	return m_permGenSpinBox->isVisible();
+}
+
+int JavaSettingsWidget::permGenSize() const
+{
+	return m_permGenSpinBox->value();
+}
+
+void JavaSettingsWidget::memoryValueChanged(int)
+{
+	bool actuallyChanged = false;
+	int min = m_minMemSpinBox->value();
+	int max = m_maxMemSpinBox->value();
+	int permgen = m_permGenSpinBox->value();
+	QObject *obj = sender();
+	if (obj == m_minMemSpinBox && min != observedMinMemory)
+	{
+		observedMinMemory = min;
+		actuallyChanged = true;
+		if (min > max)
+		{
+			observedMaxMemory = min;
+			m_maxMemSpinBox->setValue(min);
+		}
+	}
+	else if (obj == m_maxMemSpinBox && max != observedMaxMemory)
+	{
+		observedMaxMemory = max;
+		actuallyChanged = true;
+		if (min > max)
+		{
+			observedMinMemory = max;
+			m_minMemSpinBox->setValue(max);
+		}
+	}
+	else if (obj == m_permGenSpinBox && permgen != observedPermGenMemory)
+	{
+		observedPermGenMemory = permgen;
+		actuallyChanged = true;
+	}
+	if(actuallyChanged)
+	{
+		checkJavaPathOnEdit(m_javaPathTextBox->text());
+	}
+}
+
+void JavaSettingsWidget::javaVersionSelected(BaseVersionPtr version)
+{
+	auto java = std::dynamic_pointer_cast<JavaInstall>(version);
+	if(!java)
+	{
+		return;
+	}
+	auto visible = java->id.requiresPermGen();
+	m_labelPermGen->setVisible(visible);
+	m_permGenSpinBox->setVisible(visible);
+	m_javaPathTextBox->setText(java->path);
+	checkJavaPath(java->path);
+}
+
+void JavaSettingsWidget::on_javaBrowseBtn_clicked()
+{
+	QString filter;
+#if defined Q_OS_WIN32
+	filter = "Java (javaw.exe)";
+#else
+	filter = "Java (java)";
+#endif
+	QString raw_path = QFileDialog::getOpenFileName(this, tr("Find Java executable"), QString(), filter);
+	if(raw_path.isEmpty())
+	{
+		return;
+	}
+	QString cooked_path = FS::NormalizePath(raw_path);
+	m_javaPathTextBox->setText(cooked_path);
+	checkJavaPath(cooked_path);
+}
+
+void JavaSettingsWidget::on_javaStatusBtn_clicked()
+{
+	QString text;
+	bool failed = false;
+	switch(javaStatus)
+	{
+		case JavaStatus::NotSet:
+			checkJavaPath(m_javaPathTextBox->text());
+			return;
+		case JavaStatus::DoesNotExist:
+			text += QObject::tr("The specified file either doesn't exist or is not a proper executable.");
+			failed = true;
+			break;
+		case JavaStatus::DoesNotStart:
+		{
+			text += QObject::tr("The specified java binary didn't start properly.<br />");
+			auto htmlError = m_result.errorLog;
+			if(!htmlError.isEmpty())
+			{
+				htmlError.replace('\n', "<br />");
+				text += QString("<font color=\"red\">%1</font>").arg(htmlError);
+			}
+			failed = true;
+			break;
+		}
+		case JavaStatus::ReturnedInvalidData:
+		{
+			text += QObject::tr("The specified java binary returned unexpected results:<br />");
+			auto htmlOut = m_result.outLog;
+			if(!htmlOut.isEmpty())
+			{
+				htmlOut.replace('\n', "<br />");
+				text += QString("<font color=\"red\">%1</font>").arg(htmlOut);
+			}
+			failed = true;
+			break;
+		}
+		case JavaStatus::Good:
+			text += QObject::tr("Java test succeeded!<br />Platform reported: %1<br />Java version "
+				"reported: %2<br />").arg(m_result.realPlatform, m_result.javaVersion.toString());
+			break;
+		case JavaStatus::Pending:
+			// TODO: abort here?
+			return;
+	}
+	CustomMessageBox::selectable(
+		this,
+		failed ? QObject::tr("Java test success") : QObject::tr("Java test failure"),
+		text,
+		failed ? QMessageBox::Critical : QMessageBox::Information
+	)->show();
+}
+
+void JavaSettingsWidget::setJavaStatus(JavaSettingsWidget::JavaStatus status)
+{
+	javaStatus = status;
+	switch(javaStatus)
+	{
+		case JavaStatus::Good:
+			m_javaStatusBtn->setIcon(goodIcon);
+			break;
+		case JavaStatus::NotSet:
+		case JavaStatus::Pending:
+			m_javaStatusBtn->setIcon(yellowIcon);
+			break;
+		default:
+			m_javaStatusBtn->setIcon(badIcon);
+			break;
+	}
+}
+
+void JavaSettingsWidget::javaPathEdited(const QString& path)
+{
+	checkJavaPathOnEdit(path);
+}
+
+void JavaSettingsWidget::checkJavaPathOnEdit(const QString& path)
+{
+	auto realPath = FS::ResolveExecutable(path);
+	QFileInfo pathInfo(realPath);
+	if (pathInfo.baseName().toLower().contains("java"))
+	{
+		checkJavaPath(path);
+	}
+	else
+	{
+		if(!m_checker)
+		{
+			setJavaStatus(JavaStatus::NotSet);
+		}
+	}
+}
+
+void JavaSettingsWidget::checkJavaPath(const QString &path)
+{
+	if(m_checker)
+	{
+		queuedCheck = path;
+		return;
+	}
+	auto realPath = FS::ResolveExecutable(path);
+	if(realPath.isNull())
+	{
+		setJavaStatus(JavaStatus::DoesNotExist);
+		return;
+	}
+	setJavaStatus(JavaStatus::Pending);
+	m_checker.reset(new JavaChecker());
+	m_checker->m_path = path;
+	m_checker->m_minMem = m_minMemSpinBox->value();
+	m_checker->m_maxMem = m_maxMemSpinBox->value();
+	if(m_permGenSpinBox->isVisible())
+	{
+		m_checker->m_permGen = m_permGenSpinBox->value();
+	}
+	connect(m_checker.get(), &JavaChecker::checkFinished, this, &JavaSettingsWidget::checkFinished);
+	m_checker->performCheck();
+}
+
+void JavaSettingsWidget::checkFinished(JavaCheckResult result)
+{
+	m_result = result;
+	switch(result.validity)
+	{
+		case JavaCheckResult::Validity::Valid:
+		{
+			setJavaStatus(JavaStatus::Good);
+			break;
+		}
+		case JavaCheckResult::Validity::ReturnedInvalidData:
+		{
+			setJavaStatus(JavaStatus::ReturnedInvalidData);
+			break;
+		}
+		case JavaCheckResult::Validity::Errored:
+		{
+			setJavaStatus(JavaStatus::DoesNotStart);
+			break;
+		}
+	}
+	m_checker.reset();
+	if(!queuedCheck.isNull())
+	{
+		checkJavaPath(queuedCheck);
+		queuedCheck.clear();
+	}
+}
+
+void JavaSettingsWidget::retranslate()
+{
+	m_memoryGroupBox->setTitle(tr("Memory"));
+	m_maxMemSpinBox->setToolTip(tr("The maximum amount of memory Minecraft is allowed to use."));
+	m_labelMinMem->setText(tr("Minimum memory allocation:"));
+	m_labelMaxMem->setText(tr("Maximum memory allocation:"));
+	m_minMemSpinBox->setToolTip(tr("The amount of memory Minecraft is started with."));
+	m_permGenSpinBox->setToolTip(tr("The amount of memory available to store loaded Java classes."));
+	m_javaBrowseBtn->setText(tr("Browse"));
+}
diff --git a/application/widgets/JavaSettingsWidget.h b/application/widgets/JavaSettingsWidget.h
new file mode 100644
index 00000000..3a94f851
--- /dev/null
+++ b/application/widgets/JavaSettingsWidget.h
@@ -0,0 +1,102 @@
+#pragma once
+#include <QWidget>
+
+#include <java/JavaChecker.h>
+#include <BaseVersion.h>
+#include <QObjectPtr.h>
+#include <QIcon>
+
+class QLineEdit;
+class VersionSelectWidget;
+class QSpinBox;
+class QPushButton;
+class QVBoxLayout;
+class QHBoxLayout;
+class QGroupBox;
+class QGridLayout;
+class QLabel;
+class QToolButton;
+
+/**
+ * This is a widget for all the Java settings dialogs and pages.
+ */
+class JavaSettingsWidget : public QWidget
+{
+	Q_OBJECT
+
+public:
+	explicit JavaSettingsWidget(QWidget *parent);
+	virtual ~JavaSettingsWidget() {};
+
+	enum class JavaStatus
+	{
+		NotSet,
+		Pending,
+		Good,
+		DoesNotExist,
+		DoesNotStart,
+		ReturnedInvalidData
+	} javaStatus = JavaStatus::NotSet;
+
+	enum class ValidationStatus
+	{
+		Bad,
+		JavaBad,
+		AllOK
+	};
+
+	void refresh();
+	void initialize();
+	ValidationStatus validate();
+	void retranslate();
+
+	bool permGenEnabled() const;
+	int permGenSize() const;
+	int minHeapSize() const;
+	int maxHeapSize() const;
+	QString javaPath() const;
+
+
+protected slots:
+	void memoryValueChanged(int);
+	void javaPathEdited(const QString &path);
+	void javaVersionSelected(BaseVersionPtr version);
+	void on_javaBrowseBtn_clicked();
+	void on_javaStatusBtn_clicked();
+	void checkFinished(JavaCheckResult result);
+
+protected: /* methods */
+	void checkJavaPathOnEdit(const QString &path);
+	void checkJavaPath(const QString &path);
+	void setJavaStatus(JavaStatus status);
+	void setupUi();
+
+private: /* data */
+	VersionSelectWidget *m_versionWidget = nullptr;
+	QVBoxLayout *m_verticalLayout = nullptr;
+
+	QLineEdit * m_javaPathTextBox = nullptr;
+	QPushButton * m_javaBrowseBtn = nullptr;
+	QToolButton * m_javaStatusBtn = nullptr;
+	QHBoxLayout *m_horizontalLayout = nullptr;
+
+	QGroupBox *m_memoryGroupBox = nullptr;
+	QGridLayout *m_gridLayout_2 = nullptr;
+	QSpinBox *m_maxMemSpinBox = nullptr;
+	QLabel *m_labelMinMem = nullptr;
+	QLabel *m_labelMaxMem = nullptr;
+	QSpinBox *m_minMemSpinBox = nullptr;
+	QLabel *m_labelPermGen = nullptr;
+	QSpinBox *m_permGenSpinBox = nullptr;
+	QIcon goodIcon;
+	QIcon yellowIcon;
+	QIcon badIcon;
+
+	int observedMinMemory = 0;
+	int observedMaxMemory = 0;
+	int observedPermGenMemory = 0;
+	QString queuedCheck;
+	uint64_t m_availableMemory = 0ull;
+	shared_qobject_ptr<JavaChecker> m_checker;
+	JavaCheckResult m_result;
+};