diff --git a/backend/src/main/kotlin/hu/bme/sch/cmsch/admin/GenerateOverview.kt b/backend/src/main/kotlin/hu/bme/sch/cmsch/admin/GenerateOverview.kt
index 4959fb7ae..69f16e79e 100644
--- a/backend/src/main/kotlin/hu/bme/sch/cmsch/admin/GenerateOverview.kt
+++ b/backend/src/main/kotlin/hu/bme/sch/cmsch/admin/GenerateOverview.kt
@@ -41,16 +41,33 @@ fun GenerateOverview.sorter(): String {
     }
 }
 
-fun GenerateOverview.extra(): String {
+fun GenerateOverview.formatValue(value: Any?): Any =
+    if (renderer == OVERVIEW_TYPE_CDN_IMAGE) {
+        if (value is String && value.isNotBlank())
+            "/cdn/${cdnImageFolder}/${value}"
+        else
+            "data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==" // empty image
+    } else if (renderer == OVERVIEW_TYPE_TEXT || renderer == OVERVIEW_TYPE_ICON) {
+        value ?: ""
+    } else {
+        value ?: 0
+    }
+
+fun GenerateOverview.extra(): Array<Pair<String, Any>> {
     return when (this.renderer) {
-        OVERVIEW_TYPE_ID -> ", \"width\":100, \"vertAlign\":\"middle\", \"visible\":false"
-        OVERVIEW_TYPE_TEXT -> ", \"vertAlign\":\"middle\""
-        OVERVIEW_TYPE_DATE -> ", \"vertAlign\":\"middle\",\"formatter\":\"datetime\""
-        OVERVIEW_TYPE_BOOLEAN -> ", \"formatter\":\"tickCross\", \"width\":120"
-        OVERVIEW_TYPE_CDN_IMAGE -> ", \"formatter\":\"image\", \"width\":120, \"formatterParams\":{\"height\":\"100px\"}"
-        OVERVIEW_TYPE_TIME -> ", \"vertAlign\":\"middle\""
-        OVERVIEW_TYPE_NUMBER -> ", \"vertAlign\":\"middle\""
-        OVERVIEW_TYPE_ICON -> ", \"vertAlign\":\"middle\", \"formatter\":\"enumIconsFormatter\", \"width\":120"
-        else -> ""
+        OVERVIEW_TYPE_ID -> arrayOf("width" to 100, "vertAlign" to "middle", "visible" to false)
+        OVERVIEW_TYPE_TEXT -> arrayOf("vertAlign" to "middle")
+        OVERVIEW_TYPE_DATE -> arrayOf("vertAlign" to "middle", "formatter" to "datetime")
+        OVERVIEW_TYPE_BOOLEAN -> arrayOf("formatter" to "tickCross", "width" to 120)
+        OVERVIEW_TYPE_CDN_IMAGE -> arrayOf(
+            "formatter" to "image",
+            "width" to 120,
+            "formatterParams" to mapOf("height" to "100px")
+        )
+
+        OVERVIEW_TYPE_TIME -> arrayOf("vertAlign" to "middle")
+        OVERVIEW_TYPE_NUMBER -> arrayOf("vertAlign" to "middle")
+        OVERVIEW_TYPE_ICON -> arrayOf("vertAlign" to "middle", "formatter" to "enumIconsFormatter", "width" to 120)
+        else -> emptyArray()
     }
 }
diff --git a/backend/src/main/kotlin/hu/bme/sch/cmsch/admin/OverviewBuilder.kt b/backend/src/main/kotlin/hu/bme/sch/cmsch/admin/OverviewBuilder.kt
index 43a565f82..8b434e099 100644
--- a/backend/src/main/kotlin/hu/bme/sch/cmsch/admin/OverviewBuilder.kt
+++ b/backend/src/main/kotlin/hu/bme/sch/cmsch/admin/OverviewBuilder.kt
@@ -1,8 +1,5 @@
 package hu.bme.sch.cmsch.admin
 
-import com.fasterxml.jackson.core.type.TypeReference
-import com.fasterxml.jackson.databind.ObjectMapper
-import hu.bme.sch.cmsch.controller.admin.ControlAction
 import java.io.ByteArrayOutputStream
 import kotlin.reflect.KClass
 import kotlin.reflect.KProperty1
@@ -15,51 +12,37 @@ class OverviewBuilder<T : Any>(val type: KClass<T>) {
 
     private fun getColumnDefinitions(): List<Pair<KProperty1<T, *>, GenerateOverview>> {
         return type.memberProperties.asSequence()
-                .filter { it.findAnnotation<GenerateOverview>() != null }
-                .map { Pair(it, it.findAnnotation<GenerateOverview>()!!) }
-                .filter { it.second.visible }
-                .sortedBy { it.second.order }
-                .toList()
+            .filter { it.findAnnotation<GenerateOverview>() != null }
+            .map { Pair(it, it.findAnnotation<GenerateOverview>()!!) }
+            .filter { it.second.visible }
+            .sortedBy { it.second.order }
+            .toList()
     }
 
-    fun getColumnsAsJson(): String {
-        return "[" + (getColumnDefinitions().joinToString(",") {
-            "{\"title\":\"${it.second.columnName}\", " +
-                    "\"field\":\"${it.first.name}\", " +
-                    "\"hozAlign\":\"${it.second.alignment()}\", " +
-                    "\"sorter\":\"${it.second.sorter()}\"" +
-                    it.second.extra() +
-                    "}"
-        }) + "]"
+    fun getColumns(): List<Map<String, Any>> = getColumnDefinitions().map {
+        mapOf(
+            "title" to it.second.columnName,
+            "field" to it.first.name,
+            "hozAlign" to it.second.alignment(),
+            "sorter" to it.second.sorter(),
+            *it.second.extra()
+        )
     }
 
-    private fun formatValue(type: GenerateOverview, value: Any?): String {
-        return if (type.renderer == OVERVIEW_TYPE_CDN_IMAGE) {
-            if (value is String && !value.isNullOrBlank())
-                "\"/cdn/${type.cdnImageFolder}/${value}\""
-            else
-                "\"data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==\"" // empty image
-        } else if (type.renderer == OVERVIEW_TYPE_TEXT || type.renderer == OVERVIEW_TYPE_ICON) {
-            "\"${(value ?: "").toString().replace("\"", "")}\""
-        } else {
-            (value ?: "0").toString().replace("\"", "")
-        }
-    }
-
-    fun getTableDataAsJson(overview: Iterable<T>): String {
+    fun getTableData(overview: Iterable<T>): List<Map<String, Any>> {
         val fields = getColumnDefinitions()
-        return "[" + (overview.toList()
-            .map { row -> fields.map { "\"${it.first.name}\":${formatValue(it.second, it.first.get(row))}" } }
-            .joinToString(",") { row -> "{${row.joinToString(",")}}" }) + "]"
+        return overview.map { row ->
+            fields.map { it.first.name to it.second.formatValue(it.first.get(row)) }.toMap()
+        }
     }
 
     fun getInputs(): List<Pair<KProperty1<out Any, *>, GenerateInput>> {
         return type.memberProperties.asSequence()
-                .filter { it.findAnnotation<GenerateInput>() != null }
-                .map { Pair(it, it.findAnnotation<GenerateInput>()!!) }
-                .filter { it.second.visible }
-                .sortedBy { it.second.order }
-                .toList()
+            .filter { it.findAnnotation<GenerateInput>() != null }
+            .map { Pair(it, it.findAnnotation<GenerateInput>()!!) }
+            .filter { it.second.visible }
+            .sortedBy { it.second.order }
+            .toList()
     }
 
     fun exportToCsv(entities: List<T>): String {
@@ -67,13 +50,6 @@ class OverviewBuilder<T : Any>(val type: KClass<T>) {
         csv.exportToCsv(entities, outputStream)
         return outputStream.toString().trim()
     }
-
-    fun toJson(list: List<ControlAction>, objectMapper: ObjectMapper): String {
-        return objectMapper
-            .writerFor(object : TypeReference<List<ControlAction>>() {})
-            .writeValueAsString(list)
-    }
-
 }
 
 object DetailsHelper {
diff --git a/backend/src/main/kotlin/hu/bme/sch/cmsch/component/app/MenuAdminController.kt b/backend/src/main/kotlin/hu/bme/sch/cmsch/component/app/MenuAdminController.kt
index 6b4758871..53e04264e 100644
--- a/backend/src/main/kotlin/hu/bme/sch/cmsch/component/app/MenuAdminController.kt
+++ b/backend/src/main/kotlin/hu/bme/sch/cmsch/component/app/MenuAdminController.kt
@@ -114,13 +114,11 @@ class MenuAdminController(
         model.addAttribute("description", description)
         model.addAttribute("view", view)
 
-        model.addAttribute("columnData", overviewDescriptor.getColumnsAsJson())
-        model.addAttribute("tableData", overviewDescriptor.getTableDataAsJson(fetchOverview()))
+        model.addAttribute("columnData", overviewDescriptor.getColumns())
+        model.addAttribute("tableData", overviewDescriptor.getTableData(fetchOverview()))
 
         model.addAttribute("user", user)
-        model.addAttribute("controlActions", overviewDescriptor.toJson(
-            controlActions.filter { it.permission.validate(user) },
-            objectMapper))
+        model.addAttribute("controlActions", controlActions.filter { it.permission.validate(user) })
         model.addAttribute("allControlActions", controlActions)
         model.addAttribute("buttonActions", buttonActions)
 
diff --git a/backend/src/main/kotlin/hu/bme/sch/cmsch/component/task/TaskAdminRateController.kt b/backend/src/main/kotlin/hu/bme/sch/cmsch/component/task/TaskAdminRateController.kt
index 4ccaced83..83d117418 100644
--- a/backend/src/main/kotlin/hu/bme/sch/cmsch/component/task/TaskAdminRateController.kt
+++ b/backend/src/main/kotlin/hu/bme/sch/cmsch/component/task/TaskAdminRateController.kt
@@ -120,16 +120,14 @@ class TaskAdminRateController(
         model.addAttribute("titleSingular", titleSingular)
         model.addAttribute("view", view)
 
-        model.addAttribute("columnData", descriptor.getColumnsAsJson())
+        model.addAttribute("columnData", descriptor.getColumns())
         val submissions = transactionManager.transaction(readOnly = true) {
             submittedRepository.findByTask_IdAndRejectedIsFalseAndApprovedIsFalseWithoutLobs(id)
         }
-        model.addAttribute("tableData", descriptor.getTableDataAsJson(submissions))
+        model.addAttribute("tableData", descriptor.getTableData(submissions))
 
         model.addAttribute("user", user)
-        model.addAttribute("controlActions", descriptor.toJson(
-            rateControlActions.filter { it.permission.validate(user) },
-            objectMapper))
+        model.addAttribute("controlActions", rateControlActions.filter { it.permission.validate(user) })
         model.addAttribute("allControlActions", rateControlActions)
         model.addAttribute("buttonActions", buttonActions.filter { it.permission.validate(user) })
 
diff --git a/backend/src/main/kotlin/hu/bme/sch/cmsch/controller/admin/FilesByViewController.kt b/backend/src/main/kotlin/hu/bme/sch/cmsch/controller/admin/FilesByViewController.kt
index ed8f1264b..1e08e6ad0 100644
--- a/backend/src/main/kotlin/hu/bme/sch/cmsch/controller/admin/FilesByViewController.kt
+++ b/backend/src/main/kotlin/hu/bme/sch/cmsch/controller/admin/FilesByViewController.kt
@@ -90,13 +90,11 @@ class FilesByViewController(
         model.addAttribute("description", description)
         model.addAttribute("view", view)
 
-        model.addAttribute("columnData", overviewDescriptor.getColumnsAsJson())
-        model.addAttribute("tableData", overviewDescriptor.getTableDataAsJson(fetchOverview()))
+        model.addAttribute("columnData", overviewDescriptor.getColumns())
+        model.addAttribute("tableData", overviewDescriptor.getTableData(fetchOverview()))
 
         model.addAttribute("user", user)
-        model.addAttribute("controlActions", overviewDescriptor.toJson(
-            controlActions.filter { it.permission.validate(user) },
-            objectMapper))
+        model.addAttribute("controlActions", controlActions.filter { it.permission.validate(user) })
         model.addAttribute("allControlActions", controlActions)
         model.addAttribute("buttonActions", listOf<ButtonAction>())
 
@@ -126,8 +124,8 @@ class FilesByViewController(
         model.addAttribute("description", description)
         model.addAttribute("view", view)
 
-        model.addAttribute("columnData", submittedDescriptor.getColumnsAsJson())
-        model.addAttribute("tableData", submittedDescriptor.getTableDataAsJson(listFilesInView(id)))
+        model.addAttribute("columnData", submittedDescriptor.getColumns())
+        model.addAttribute("tableData", submittedDescriptor.getTableData(listFilesInView(id)))
 
         model.addAttribute("user", user)
         val controlActionForCategory = listOf(
@@ -152,9 +150,7 @@ class FilesByViewController(
                 basic = true
             )
         )
-        model.addAttribute("controlActions", overviewDescriptor.toJson(
-            controlActionForCategory.filter { it.permission.validate(user) },
-            objectMapper))
+        model.addAttribute("controlActions", controlActionForCategory.filter { it.permission.validate(user) })
         model.addAttribute("allControlActions", controlActionForCategory)
         model.addAttribute("buttonActions", listOf<ButtonAction>())
 
diff --git a/backend/src/main/kotlin/hu/bme/sch/cmsch/controller/admin/OneDeepEntityPage.kt b/backend/src/main/kotlin/hu/bme/sch/cmsch/controller/admin/OneDeepEntityPage.kt
index 68d41069b..69ce7c7e8 100644
--- a/backend/src/main/kotlin/hu/bme/sch/cmsch/controller/admin/OneDeepEntityPage.kt
+++ b/backend/src/main/kotlin/hu/bme/sch/cmsch/controller/admin/OneDeepEntityPage.kt
@@ -283,14 +283,12 @@ open class OneDeepEntityPage<T : IdentifiableEntity>(
         model.addAttribute("description", description)
         model.addAttribute("view", view)
 
-        model.addAttribute("columnData", descriptor.getColumnsAsJson())
+        model.addAttribute("columnData", descriptor.getColumns())
         val overview = transactionManager.transaction(readOnly = true) { fetchOverview(user) }
-        model.addAttribute("tableData", descriptor.getTableDataAsJson(filterOverview(user, overview)))
+        model.addAttribute("tableData", descriptor.getTableData(filterOverview(user, overview)))
 
         model.addAttribute("user", user)
-        model.addAttribute("controlActions", descriptor.toJson(
-            controlActions.filter { it.permission.validate(user) },
-            objectMapper))
+        model.addAttribute("controlActions", controlActions.filter { it.permission.validate(user) })
         model.addAttribute("allControlActions", controlActions)
         model.addAttribute("buttonActions", buttonActions.filter { it.permission.validate(user) })
         model.addAttribute("searchSettings", searchSettings)
diff --git a/backend/src/main/kotlin/hu/bme/sch/cmsch/controller/admin/TwoDeepEntityPage.kt b/backend/src/main/kotlin/hu/bme/sch/cmsch/controller/admin/TwoDeepEntityPage.kt
index ac6292465..fa2fb6abd 100644
--- a/backend/src/main/kotlin/hu/bme/sch/cmsch/controller/admin/TwoDeepEntityPage.kt
+++ b/backend/src/main/kotlin/hu/bme/sch/cmsch/controller/admin/TwoDeepEntityPage.kt
@@ -137,14 +137,12 @@ abstract class TwoDeepEntityPage<OUTER : IdentifiableEntity, INNER: Identifiable
         model.addAttribute("description", description)
         model.addAttribute("view", view)
 
-        model.addAttribute("columnData", outerDescriptor.getColumnsAsJson())
+        model.addAttribute("columnData", outerDescriptor.getColumns())
         val overview = transactionManager.transaction(readOnly = true) { fetchOuterOverview() }
-        model.addAttribute("tableData", outerDescriptor.getTableDataAsJson(overview))
+        model.addAttribute("tableData", outerDescriptor.getTableData(overview))
 
         model.addAttribute("user", user)
-        model.addAttribute("controlActions", outerDescriptor.toJson(
-            outerControlActions.filter { it.permission.validate(user) },
-            objectMapper))
+        model.addAttribute("controlActions", outerControlActions.filter { it.permission.validate(user) })
         model.addAttribute("allControlActions", outerControlActions)
         model.addAttribute("buttonActions", buttonActions.filter { it.permission.validate(user) })
 
@@ -174,14 +172,12 @@ abstract class TwoDeepEntityPage<OUTER : IdentifiableEntity, INNER: Identifiable
         model.addAttribute("description", description)
         model.addAttribute("view", view)
 
-        model.addAttribute("columnData", descriptor.getColumnsAsJson())
+        model.addAttribute("columnData", descriptor.getColumns())
         val overview = transactionManager.transaction(readOnly = true) { filterOverview(user, fetchSublist(id)) }
-        model.addAttribute("tableData", descriptor.getTableDataAsJson(overview))
+        model.addAttribute("tableData", descriptor.getTableData(overview))
 
         model.addAttribute("user", user)
-        model.addAttribute("controlActions", descriptor.toJson(
-            controlActions.filter { it.permission.validate(user) },
-            objectMapper))
+        model.addAttribute("controlActions", controlActions.filter { it.permission.validate(user) })
         model.addAttribute("allControlActions", controlActions)
         model.addAttribute("buttonActions", buttonActions.filter { it.permission.validate(user) })
 
diff --git a/backend/src/main/kotlin/hu/bme/sch/cmsch/controller/auditlog/AuditLogController.kt b/backend/src/main/kotlin/hu/bme/sch/cmsch/controller/auditlog/AuditLogController.kt
index c64198ccb..8c7325303 100644
--- a/backend/src/main/kotlin/hu/bme/sch/cmsch/controller/auditlog/AuditLogController.kt
+++ b/backend/src/main/kotlin/hu/bme/sch/cmsch/controller/auditlog/AuditLogController.kt
@@ -91,13 +91,11 @@ class AuditLogController(
         model.addAttribute("description", description)
         model.addAttribute("view", view)
 
-        model.addAttribute("columnData", descriptor.getColumnsAsJson())
-        model.addAttribute("tableData", descriptor.getTableDataAsJson(listFilesInView()))
+        model.addAttribute("columnData", descriptor.getColumns())
+        model.addAttribute("tableData", descriptor.getTableData(listFilesInView()))
 
         model.addAttribute("user", user)
-        model.addAttribute("controlActions", descriptor.toJson(
-            controlActions.filter { it.permission.validate(user) },
-            objectMapper))
+        model.addAttribute("controlActions", controlActions.filter { it.permission.validate(user) })
         model.addAttribute("allControlActions", controlActions)
         model.addAttribute("buttonActions", listOf<ButtonAction>())
 
diff --git a/backend/src/main/kotlin/hu/bme/sch/cmsch/controller/userhandling/PermissionGroupAssignPage.kt b/backend/src/main/kotlin/hu/bme/sch/cmsch/controller/userhandling/PermissionGroupAssignPage.kt
index 406cd2d9e..6e39ba0ce 100644
--- a/backend/src/main/kotlin/hu/bme/sch/cmsch/controller/userhandling/PermissionGroupAssignPage.kt
+++ b/backend/src/main/kotlin/hu/bme/sch/cmsch/controller/userhandling/PermissionGroupAssignPage.kt
@@ -129,7 +129,7 @@ class PermissionGroupAssignPage(
         model.addAttribute("description", "Válassz, hogy melyik felhasználó kapja meg a(z) ${permissionGroup.displayName} jogkört")
         model.addAttribute("view", view)
 
-        model.addAttribute("columnData", descriptor.getColumnsAsJson())
+        model.addAttribute("columnData", descriptor.getColumns())
         val overview = transactionManager.transaction(readOnly = true) {
             userRepository.findAll()
                 .filter { permissionGroup.key.isNotEmpty() && !it.permissionGroups.split(",").contains(permissionGroup.key) }
@@ -143,12 +143,10 @@ class PermissionGroupAssignPage(
                     )
                 }
         }
-        model.addAttribute("tableData", descriptor.getTableDataAsJson(filterOverview(user, overview)))
+        model.addAttribute("tableData", descriptor.getTableData(filterOverview(user, overview)))
 
         model.addAttribute("user", user)
-        model.addAttribute("controlActions", descriptor.toJson(
-            controlActionsForView.filter { it.permission.validate(user) },
-            objectMapper))
+        model.addAttribute("controlActions", controlActionsForView.filter { it.permission.validate(user) })
         model.addAttribute("allControlActions", controlActionsForView)
         model.addAttribute("buttonActions", buttonActionsForView.filter { it.permission.validate(user) })
         model.addAttribute("searchSettings", searchSettings)
@@ -188,4 +186,3 @@ class PermissionGroupAssignPage(
     fun redirectToUsersView(@PathVariable id: Int) = "redirect:/admin/control/permission-groups-for-users/${id}"
 
 }
-
diff --git a/backend/src/main/kotlin/hu/bme/sch/cmsch/controller/userhandling/PermissionGroupUserListPage.kt b/backend/src/main/kotlin/hu/bme/sch/cmsch/controller/userhandling/PermissionGroupUserListPage.kt
index f734a8c7f..f762a1e0d 100644
--- a/backend/src/main/kotlin/hu/bme/sch/cmsch/controller/userhandling/PermissionGroupUserListPage.kt
+++ b/backend/src/main/kotlin/hu/bme/sch/cmsch/controller/userhandling/PermissionGroupUserListPage.kt
@@ -140,7 +140,7 @@ class PermissionGroupUserListPage(
         model.addAttribute("description", description)
         model.addAttribute("view", view)
 
-        model.addAttribute("columnData", descriptor.getColumnsAsJson())
+        model.addAttribute("columnData", descriptor.getColumns())
         val overview = transactionManager.transaction(readOnly = true) {
             userRepository.findAllByPermissionGroupsNot("")
                 .filter { permissionGroup.key.isNotEmpty() && it.permissionGroups.split(",").contains(permissionGroup.key) }
@@ -154,12 +154,10 @@ class PermissionGroupUserListPage(
                     )
                 }
         }
-        model.addAttribute("tableData", descriptor.getTableDataAsJson(filterOverview(user, overview)))
+        model.addAttribute("tableData", descriptor.getTableData(filterOverview(user, overview)))
 
         model.addAttribute("user", user)
-        model.addAttribute("controlActions", descriptor.toJson(
-            controlActionsForView.filter { it.permission.validate(user) },
-            objectMapper))
+        model.addAttribute("controlActions", controlActionsForView.filter { it.permission.validate(user) })
         model.addAttribute("allControlActions", controlActionsForView)
         model.addAttribute("buttonActions", buttonActionsForView.filter { it.permission.validate(user) })
         model.addAttribute("searchSettings", searchSettings)
@@ -201,4 +199,3 @@ class PermissionGroupUserListPage(
     fun redirectToUsersView() = "redirect:/admin/control/permission-groups"
 
 }
-
diff --git a/backend/src/main/resources/templates/overview4.html b/backend/src/main/resources/templates/overview4.html
index 3be055bed..d0ad70e93 100644
--- a/backend/src/main/resources/templates/overview4.html
+++ b/backend/src/main/resources/templates/overview4.html
@@ -110,8 +110,8 @@ <h5 th:text="${action.usageString}">Usage text</h5>
         return dt.toFormat("yyyy-MM-dd HH:mm");
     }
 
-    const buttons = JSON.parse(/*[[${controlActions}]]*/ "[]");
-    let tableData = JSON.parse(/*[[${tableData}]]*/ "[]");
+    const buttons = /*[[${controlActions}]]*/ [];
+    let tableData = /*[[${tableData}]]*/ [];
     let view = /*[[${view}]]*/ "";
     for (let rowId in tableData) {
         const row = tableData[rowId];
@@ -140,7 +140,7 @@ <h5 th:text="${action.usageString}">Usage text</h5>
         return enumElementMap[value] || "";
     }
 
-    let columData = JSON.parse(/*[[${columnData}]]*/ "[]");
+    let columData = /*[[${columnData}]]*/ [];
     for (let columnId in columData) {
         if (columData[columnId].formatter === 'tickCross') {
             columData[columnId]['formatterParams'] = {